This question comes up roughly once every 6 weeks ...... Chopping your vocal into smaller sections is one option. Using the original record the acapella is from is the best way to work out the right bpm of it.
If you have th record usaully on the other side theu have the vocals w/ the beat, and you could just beat match it that way. And if you do have the record find the song itself and beatmatch it that way
I always think that someone who makes beats would have an ear for doing this kind of thing!
It's real simple and it amazes me how many people still get it so wrong! I mean, theres some tracks that are harder to match than others but still, it's not hard.
my experience w/ the beatmapper( ha). Man that function in Acid is such a joke. For me I just use the tap tempo on my kaoss pad, and just round the bpm to the tempo I would prefer havinig it at