I dont recommend using acid for a finishing recording. The record feature is good to help you lay out and test the drum tracks you've written but thats it.. unless you have a $500 sound card.....
As far as Acid for midi
Thats craziness to me...
I hate the way midi sounds.
save all your sessions as the standard acid file and then when you complete a full drum track of your song, go to file, save as, and select wav.
this way you can import the drums to just about any recording software available.
heres what i do:
write the drums in acid, record guitar and bass in acid as test tracks on;y to make sure the timing is all correct..
save entire session as an acid file.
re open that file, delete all but the drum tracks and click save as WAV.
now you have your Acid file with all the tests etc and you have a seperate WAV file with only the drums.
(acid can still play it as a wav)
Then I open up Cool Edit Pro,
import the WAv drum file and record guitars, bass, keys vocals whatever.
Mix, Eq, master whatever and mix it down as a stereo track.
Then convert to MP3 if you desire.
its that simple....