Here is the final result.

The problem is related to using such an approach on COM mode. I changed WWC into file mode so I could see what was going on. From that mode, I was able to run the application without any problem. The sub class was created from the main class between both EXEs. However, as soon as I switch WWC to COM mode, the application will hang at the CREATEOBJECT() line where a sub class is about to be created from the main class which resides in the other EXE.

This is quite insulting to face such a bug as I can't see any workaround for that. I really need to run the Web application in COM mode.