Igor,
Your information is somewhat contradictory.
On one hand you, say the the code runs, but that certain functions that are called, are not in the code. So I must assume that when you "test" the code, you are not testing all of the functionality, as otherwise if one of the missing functions were called, then the code would fail.
How is this so? You could try adding some code the call these "missing" functions and see what happens.
You should compare the "prm" file from the "old" project to the "prm" file of the 512 project, and reconcile the differences. What errors specifically do you get when you build the converted project?