Convert the file into wav ... sf or wavelab should do it!
In fruity, load it the sample 2 a channel... now click on its name 2 get the properties... U should find a small screen with the wave, on top of this there is a little field that looks like this STEP : - -, change the number of steps... example : If yer sample is one bar long (and u r working with a 16 step pattern) just type 16!! ... 32 for 2 bars and so on...
The only shi*y bit about this is that it will always play at the same tone (pitch)... the time streaching that fruity does is preaty reasonable... some time the sound gets a bit fuc**d, but sometimes that same prob. makes the sample sound a little different,... dare I say Unique!! :P
Hope this helpz,
Z