WIX installer: set additional text to exit dialog using custom action - wix

Question

I am installing ASP.NET MVC website using wix. I need to show the URL of installed site on the exit screen.
I have following properties:
<Property Id="WEBSITE_URL" Value="NotSet" />
<Property Id="WIXUI_EXITDIALOGOPTIONALTEXT" Value="NotSet" />
Which are populated using custom actions:
<CustomAction Id="GetWebsiteUrl"
BinaryKey="CustomActions"
DllEntry="GetWebsiteUrl"
Execute="immediate"
Return="ignore" />
<CustomAction Id="SetExitDialogAdditionalText"
Property="WIXUI_EXITDIALOGOPTIONALTEXT"
Value="The API may be accessed from the following URL: [WEBSITE_URL]"/>
InstallUISequence is following:
<InstallUISequence>
<Custom Action='GetWebsiteUrl' Before='ExecuteAction'>NOT Installed AND NOT REMOVE</Custom>
<Custom Action="SetExitDialogAdditionalText" After="GetWebsiteUrl">NOT Installed AND NOT REMOVE</Custom>
</InstallUISequence>
And the result string on exit screen is:
The API may be accessed from the following URL: NotSet
I've tried to execute custom actions in the InstallExecuteSequence and in the logs I can see that string looks correct:
<InstallExecuteSequence>
<Custom Action='GetWebsiteUrl' Before='InstallFinalize'>NOT Installed AND NOT REMOVE</Custom>
<Custom Action="SetExitDialogAdditionalText" After="GetWebsiteUrl">NOT Installed AND NOT REMOVE</Custom>
</InstallExecuteSequence>
The result in logs:
PROPERTY CHANGE: Modifying WEBSITE_URL property. Its current value is
'NotSet'. Its new value: 'http://localhost:80'.
PROPERTY CHANGE: Modifying WIXUI_EXITDIALOGOPTIONALTEXT property. Its
current value is 'NotSet'. Its new value: 'The API may be
accessed from the following URL: http://localhost:80'.
But in UI something is going wrong.
I feel like the problem is in the InstallUISequence, but can't understand what I'm doing wrong. Please advise.

Answer 1

Try declaring your WEBSITE_URL property as secure in case the value isn't being properly saved across UI and Execute sequences.