FireOnOKProgId iCommand for send and file customisation

System

The 8.5 client customisation guide mentions the ability to put a custom command when a user sends and files an email:

HKEY_CURRENT_USER\Software\Interwoven\WorkSite\8.0\EMM\Config\
Create the following STRING value:
Name: FireOnOKProgId
Value: TestCommand.TestICommand

We have tried this, but the iCommand never seems to execute. Anyone have any ideas on how to gert this to work ?