Linux Output sound via HDMI *and* analogue

I've got XBMC Eden (Actually Eden Beta 3 on Openelec) running, and it's fantastic.

I've got sound output currently via the HDMI cable to the receiver, which then sends it to all the speakers.

My problem: When playing music (and potentially at other times), I would like to send the output via the HDMI *and* the analogue output on my computer (an Acer Aspire Revo 3700).

Why?: Because I have a whole-house speaker system that will only take an analogue input, and the receiver can't seem to split the HDMI input to both speakers and an analog out (probably think I'm trying to decrypt bluray or something).

Is there a way to do this?

I'm okay with always output to both HDMI and analogue, if that's a viable option.

http://forum.xbmc.org/showthread.php?tid=86038