midi control SW sampler live/hands free

[Rich Schiavi <rich@nalutech.com>]

for a guitarist/echoplex users, i want to be able to trigger samples from 
software samplers. i'm looking at acid pro and ableton, and looking at 
unity. 
my main question is, i'm trying to figure out a way to use a midi foot 
controller to select a particular sample (or program or sample from a 
bank?) 
and start/stop that particular sample, all from a midi foot controller so 
i can 
keep my hands on the guitar/etc/instrument.

has anyone got this working? i messed around with my rolls midi buddy and 
ableton and acid pro but couldn't see anything to get it to select and 
trigger 
a sample to start playing (continuous) or one time, etc.

thanks for ideas/suggestions.

rich