out that little list of programs, i would use acid 6.0 if i was you…
bring in your sample, acapella… to the mix/project then it may ask you if you want to beatmap it… you do, so click yes..
get your mappin n that sorted, then after that paint in your pella/sample where ever you want it, right click on the parts and go to clip properties you should notice a box that says " Preserve pitch when stretching " tick it.. if its already ticked then things are fine 
theres other options there too, like the mode… this is really to let you fine tune the pitch change compensation process, depending on what your using you’ll find an option to suit you, its all really to do with how the samples chopped up an squashed back together, trial and error should let you find the mode more suited to what your wanting…
well now you’ve got your pella set to the original pitch, going at the desired tempo… you should see another option in the clip properties " pitch shift "
not going to patronise you with telling you what to do from there, should be all straightforward enough now 
hopefully thats been of some help to you m8…well i better finish geting ready for college so
til nxt time…
andymac
