Remove from one side of the many to many in Nhibernate - nhibernate

Question

I have these 2 objects in NHibernate forming a many to many relationship:
User:
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
assembly="Providers" namespace="Providers.Objects">
<class name="User" table="Users">
<id name="UserId" type="int">
<generator class="native" />
</id>
<many-to-one name="Application" column="ApplicationId" cascade="none" />
<property name="UserName" type="string" />
<property name="LoweredUserName" type="string" />
<property name="MobileAlias" type="string" />
<property name="IsAnonymous" type="bool" />
<property name="LastActivityDate" type="DateTime" />
<bag name="Roles" table="UsersInRoles" lazy="true" cascade="none" >
<key column="UserId"></key>
<many-to-many class="Role" column="RoleId"></many-to-many>
</bag>
</class>
</hibernate-mapping>
And Role:
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
assembly="Providers" namespace="Providers.Objects">
<class name="Role" table="Roles">
<id name="RoleId" type="int">
<generator class="native" />
</id>
<many-to-one name="Application" column="ApplicationId" class="Application" cascade="none" />
<property name="RoleName" type="string" />
<property name="LoweredRoleName" type="string" />
<property name="Description" type="string" />
<bag name="Users" table="UsersInRoles" lazy="true" inverse="true" cascade="none" >
<key column="RoleId"></key>
<many-to-many class="User" column="UserId"></many-to-many>
</bag>
</class>
</hibernate-mapping>
Let's say the role backupoperator has some users in it. If I try to remove one of the users from the role instance, like:
var backupoperator = GetRoleByName(session, app.ApplicationId, "backupoperator");
backupoperator.Users.RemoveAt(0);
session.Update(backupoperator);
transaction.Commit();
It doesn't work :( The association remains unchanged in the database. When I try the opposite (remove a role from a user object and updating the user object), it works.
Is it because of the inverse attribute in the NHibernate mapping?
How to accomplish what I am trying to do? (remove a user from a role, updating the role and having that persisted)?
Thanks

Answer 1

When you write inverse="true" you are telling NHibernate that the other side maintains the relationship.
Therefore, you have to remove the Role from the User's Roles collection if you want your change persisted.