Soundmax HD audio: Stereo Mix + Mic

[gu-val]

Hello there, I have a problem with streaming video+audio live.
The problem is, I need to put both wave output (game sounds, music, other things I hear) and Mic output into the recording channel.
I have HP probook 4510s which uses SoundMAX Integrated Digital HD Audio soundcard. Windows XP driver version 5.10.1.7265. HP site doesnt have any newer driver for this device, afaik.

Normally, I would tick both "Stereo Mix" and "Microphone" thingies in the recording control, as with my another PC (desktop one, soundcard realtek HD or something), but it works the other way around on laptop. It allows me to choose only 1 option (mix or mic) and whenever I try to check one, the second becomes unchecked.

Is there a way to check both? Maybe a driver upgrade/downgrade, or modify it somehow.
Please dont suggest me software solutions like VAC or similar, but I would really appreciate your input about driver issue.

Sorry about bad english.