You can also hit the D-pad during the actual gameplay to toggle freestyle solos on or off. The game never tells you that (to my knowledge), but there ya go.
Also, I am very disappointed with this game, coming off of Rock Band 3. No custom setlists? Whaaaat?
I tried doing this a day or two ago, because that's what I had heard, too, but it didn't seem to do anything. The only way I was able to get solos to toggle on or off was to pause the game. Not sure what's up with that.
jeff's comments