Well, best way to do this would be to create a new EXS24 instrument and import the audio file into it.
- Create a software instrument track and place an EXS24 in the top I/O slot
- Click on the Edit button in the EXS24 interface
- Drag your audio file into the main area of the Instrument Editor window
- It should be mapped across the entire keyboard. Make sure to save your instrument (Instrument > Save as...)
(Note: with percussive sounds I usually import the file onto a track in Logic, create a new empty EXS24, play them back simultaneously and play notes of the keyboard to figure out the aprox. pitch value of the percussive sound. Then, in the Instrument Editor, I'll set the "Key" for this percussive sound to that value, e.g. C2.)
You can do the same by importing a complete mix of your project into an EXS24... but the pitch shifting algorithms will also change the speed of the audio... so you might wish to try placing a "Pitch Shifter II" plug-in on the Stereo Output insert and playing with the features there.
Hope that helps