How to measure code coverage with Selenium - selenium

Question

My project is composed by a EJB module and a Web module.
The EJB module uses Arquillian with Persistence extension to run integration tests. Arquillian starts up a managed Jboss7, setup the database, run the tests and then shuts down Jboss. I have JaCoCo Maven Plugin configured to generated code coverage reports for those tests and everything is working perfectly - reports are created and exported to a sonar server.
The Web module uses Arquillian with Drone/Graphene extensions to run Selenium tests. So, during my CI build, Arquillian starts a Jboss7, starts firefox and run the Selenium test suites automatically. Here is where I'm having troubles... All the tests run just fine, however JaCoCo reports are not being generated for this module.
Both modules share a common root pom, here is the relevant bit of this pom:
<project
xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<properties>
<version.joda.time>2.1</version.joda.time>
<version.junit>4.11</version.junit>
<version.mockito>1.9.5</version.mockito>
<version.jacoco>0.6.0.201210061924</version.jacoco>
<version.arquillian.jacoco>1.0.0.Alpha5</version.arquillian.jacoco>
<version.arquillian.persistence>1.0.0.Alpha6</version.arquillian.persistence>
<version.commons.collections>3.2.1</version.commons.collections>
<version.guava.testlib>14.0.1</version.guava.testlib>
</properties>
<dependencies>
<dependency>
<groupId>joda-time</groupId>
<artifactId>joda-time</artifactId>
<version>${version.joda.time}</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>${version.junit}</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.mockito</groupId>
<artifactId>mockito-all</artifactId>
<version>${version.mockito}</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava-testlib</artifactId>
<version>${version.guava.testlib}</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>commons-collections</groupId>
<artifactId>commons-collections</artifactId>
<version>${version.commons.collections}</version>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.jboss.arquillian.extension</groupId>
<artifactId>arquillian-drone-bom</artifactId>
<version>1.2.0.Alpha2</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<dependency>
<groupId>org.jboss.arquillian</groupId>
<artifactId>arquillian-bom</artifactId>
<version>1.0.4.Final</version>
<scope>import</scope>
<type>pom</type>
</dependency>
</dependencies>
</dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.jacoco</groupId>
<artifactId>jacoco-maven-plugin</artifactId>
<version>${version.jacoco}</version>
<executions>
<execution>
<id>pre-unit-test</id>
<goals>
<goal>prepare-agent</goal>
</goals>
</execution>
<execution>
<id>post-unit-test</id>
<phase>test</phase>
<goals>
<goal>report</goal>
</goals>
</execution>
<execution>
<id>pre-integration-test</id>
<phase>pre-integration-test</phase>
<goals>
<goal>prepare-agent</goal>
</goals>
<configuration>
<destFile>target/jacoco-it.exec</destFile>
<propertyName>failsafe.argLine</propertyName>
</configuration>
</execution>
<execution>
<id>post-integration-test</id>
<phase>post-integration-test</phase>
<goals>
<goal>report</goal>
</goals>
<configuration>
<dataFile>target/jacoco-it.exec</dataFile>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-failsafe-plugin</artifactId>
<version>2.14</version>
<configuration>
<argLine>${failsafe.argLine}</argLine>
<reportsDirectory>${project.build.directory}/surefire-reports</reportsDirectory>
</configuration>
<executions>
<execution>
<id>integration-test</id>
<goals>
<goal>integration-test</goal>
</goals>
</execution>
<execution>
<id>verify</id>
<goals>
<goal>verify</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.0</version>
<configuration>
<source>1.7</source>
<target>1.7</target>
<encoding>UTF-8</encoding>
</configuration>
</plugin>
<plugin>
<groupId>com.atlassian.maven.plugins</groupId>
<artifactId>maven-jgitflow-plugin</artifactId>
<version>1.0-alpha14</version>
<configuration>
<enableFeatureVersions>true</enableFeatureVersions>
<autoVersionSubmodules>true</autoVersionSubmodules>
<pushReleases>true</pushReleases>
</configuration>
</plugin>
</plugins>
</build>
<profiles>
<profile>
<id>arquillian-jbossas-managed</id>
<activation>
<activeByDefault>true</activeByDefault>
</activation>
<build>
<plugins>
<plugin>
<artifactId>maven-dependency-plugin</artifactId>
<executions>
<execution>
<id>unpack</id>
<phase>process-test-classes</phase>
<goals>
<goal>unpack</goal>
</goals>
<configuration>
<artifactItems>
<artifactItem>
<groupId>org.jboss.as</groupId>
<artifactId>jboss-as-dist</artifactId>
<version>7.1.1.Final</version>
<type>zip</type>
<overWrite>false</overWrite>
<outputDirectory>target</outputDirectory>
</artifactItem>
</artifactItems>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
<pluginManagement>
<plugins>
<!-- Ignore/Execute plugin execution -->
<plugin>
<groupId>org.eclipse.m2e</groupId>
<artifactId>lifecycle-mapping</artifactId>
<version>1.0.0</version>
<configuration>
<lifecycleMappingMetadata>
<pluginExecutions>
<!-- copy-dependency plugin -->
<pluginExecution>
<pluginExecutionFilter>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<versionRange>[1.0.0,)</versionRange>
<goals>
<goal>unpack</goal>
</goals>
</pluginExecutionFilter>
<action>
<execute />
</action>
</pluginExecution>
</pluginExecutions>
</lifecycleMappingMetadata>
</configuration>
</plugin>
</plugins>
</pluginManagement>
<testResources>
<testResource>
<directory>src/test/resources</directory>
</testResource>
</testResources>
</build>
<dependencies>
<dependency>
<groupId>org.jboss.as</groupId>
<artifactId>jboss-as-arquillian-container-managed</artifactId>
<version>7.1.1.Final</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.jboss.arquillian.protocol</groupId>
<artifactId>arquillian-protocol-servlet</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.jboss.arquillian.extension</groupId>
<artifactId>arquillian-jacoco</artifactId>
<scope>test</scope>
<version>${version.arquillian.jacoco}</version>
</dependency>
<dependency>
<groupId>org.jacoco</groupId>
<artifactId>org.jacoco.core</artifactId>
<version>${version.jacoco}</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.jboss.arquillian.junit</groupId>
<artifactId>arquillian-junit-container</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.jboss.arquillian.junit</groupId>
<artifactId>arquillian-junit-container</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.jboss.arquillian.extension</groupId>
<artifactId>arquillian-persistence-impl</artifactId>
<version>${version.arquillian.persistence}</version>
<scope>test</scope>
</dependency>
</dependencies>
</profile>
</profiles>
</project>