Technical Requirements for Windows-Linux Application Port

Looking for some help writing some technical requirements document for some vendors to port some applications from Windows 2000 to SLES 11 (SUSE Linux Enterprise Server 11). These are either stand-alone Java applications (i.e. no app server) or C/C++ applications. We're new to porting from Windows to Linux here in our shop.

If anyone has any sample docs or big pitfalls or lessons learned to mention, it would be greatly appreciated. I think I can take care of the basics, like, don't use too much memory, or don't violate company IT Security policy, and stuff like that. Looking for those seemingly obscure things that I need to let my vendors know up front so they don't bite us in the behind later in the process.