Sound editing problems HELP

[Bassist-X]

I've been working on changing the warthog sounds and I've gotten everything including the special codec needed. I've used HMT3.5 to extract the sound files, I've changed them around recoded them in standard .wav format, but when I go to use amWave Pro to change the sounds to the xbox format it doesn't seem to work. The program says it was completed successfully but HMT3.5 (and HMTv2) give me the error that it isn't in the proper format. Can anyone suggest any good .wav encoders so that I can start getting some mods up on the files section? Thanx in Advance ~ Bassist-X