As an addendum to the extended fills,I also found it handy to substitute the parts from the "BREAK" button under an INTRO button,as the BREAK is difficult to access while playing.
Also the substitution of the simple ending(ENDING 1) in an INTRO gives you a nice stop or 1(or 2) bar pause,the style resuming afterwards.To get the drum fill to work really cool,substitute RHY 2 of the ENDING to RHY 1 of the new INTRO...this way you get the stop and the fill.