Converting sustaining keyboard sounds from other samplers?

Does anybody know a good way or software for converting instrument programs from other samplers? I've tried converting a few using Extreme Sample Converter software to Akai AKP programs, loading those into Blue Box using the AKP import, and then saving out the program in the MPC1000/2500/500 format. But somewhere along the line I lose the loop points of any sustaining keyboard programs.

Another thing I tried was converting them with Awave software to MPC1000 programs, but ended up with all the samples being stacked on a single key.

I hope this makes sense.. Any suggestions?