What C-compiler for SmartPropo (winmm.dll)

[Harm]

Hello,

I've an old Simprop SSM Contest 5 transmitter. I try to use this Simprop with the "SmartPropo DLL Version for FMS".
Both JrPPM and FutabaPPM doesn't work correctly.
Simprop has only 5 channels (=6 pulses) and timing is different.

I want to make a new winmm.dll for the Simprop.
What compiler should I use to make a new winmm.dll with a modified winmm.c file??

Harm