Help me please,

I am trying to write a program that performs menu commands on a very unhelpful application. I know I can use the postmessage command with one of the WM constants, but I am not sure which one, or what the parameters should be. Does anyone out there know how to do this.
(There is an E-Pint in it for anyone who can help me!!! - Let me have your E:Mail)

TIA

Ell