Are you outputting a PWM signal? Or did you just set the tristate to 1?
also you might want to have a look at this post of mine... it might help a little.
if you arent outputting PWM, you'll need to set up a timer or CCP to use as a PWM timebase and another CCP for each individual motor channel.... also you'll need to see what pins on the microcontroller are connected to which pins on the I/O pins...
is this what you need? either way let me know.
-q