GuitarPro4

Naw...

what you do is right click on the first note you want to acousitc, go to "mix table", then select instrument andput whatever tyou want, then on the last note you want that instrument, go back to mix table and put it back to disto guitar.
 
Yeha what needled said, mix table, then a tiny red box will appear above the starting note you want to change