Session 0 Isolation - (PostMessage/SendMessage) ??

Here's a link for info on the topic:

http://msdn.microsoft.com/en-us/libr.../bb756986.aspx

The issue I'm having is finding a way to use SendMessage, and PostMessage
for an application I've built on XP (which allows Session 0).

How can I elevate the program to Session 0, or how does someone enable SendMessage
and PostMessage to be used from Vista etc.?

You can't elevate a 'program' to Session 0. That's the whole point. Everything in Session 0 is literally deaf to messages from outside it.

is there a way to sendmessage and postmessage in vista/7/8? or a workaround/something similar, does the same thing?

Well what are you sending/posting them to and for what purpose?