Audio Output?

I recently purchased a set of Apple Pro speakers (cheap) because I thought one of my old speakers had failed. Well Now that I have the Pro speakers I would like to go ahead and use them but here's the catch. I would also like to use my sub from my old set of speakers. With the pro speakers pluged in if I plug the sub or anything else into the headphone jack in the back of the computer it will mute the Pro Speaker jack.

Is there anyway I can get output out of both the headphone jack and the digital out jack simultaneously? This way I can use the Pro speakers and my sub.

I'm looking for a system patch to make this work. If not I will sell the PRO speakers and go back to my Atlantic Tech speakers which aparently work fine.

The reason I bought the Pro speakers (besides the price) was that I thought the right sattelite of my Atlantic's had died. Well when I hooked up the Pro speakers the right channel wasn't working either. So I opened up the sound control panel and checked the output and somehow durring an update or something the system had set the stereo bias to the left channel completely shutting off the right. How this happened I do not know. All I know is that I didn't do it and that is why I didn't check there in the first place.