Simple mp3 player

Hello everyone, hope someone can help me out:

I want to create a player that loads an external mp3 file and play it.
Up to here no problem.

What I can’t figure out is how do I start the song to play from time 1.00 minute and make it stop after 20 seconds.

I achieved the stopping by calculating how much is 20 seconds (about 600 frames in my case) and inserted SoundMixer.stopAll(); command (as3). What I don’t know is how to make it play from a certain time.

Hope someone can help me out,

thanks