Marco,
Just an addendum... Not ALL Tune 1000 songs have harmonies. Also, if you have got the files from someone else ( or from the NET), they MAY have tweaked them and put that data onto another channel. Its a bit difficult for me without actually seeing the file/s in question.

But these are things you need to be aware of.

Also check out Zuki's posts above, as those methods he described are also very good for getting the harmonies you want.

Cheers
Dennis