Hi Paul,
What is the reason you wish to do this?
I'm not sure you would want to do this, as admins (and perhaps some users) would need to be able to access the Integrity server homepage in some cases. But I don't understand your use-case yet.
Probably the better option would be to simply point users to the Workflows and Documents interface with a direct URL. ex:
http://myIntegrityserver:9001/im
* note the /im
If you are asking about how to replace the Integrity server homepage with something entirely different, we have this article published:
https://www.ptc.com/appserver/cs/view/solution.jsp?n=CS000150608
But this doesn't sound like what you are looking for.