Use AUX button to adjust volume in a call

[wilk]

The volume bar in 2008.12 is a good thing but it's not very convenient to slide it when you're not using a headset. Since we don't have many buttons available, maybe we could use the AUX button, conveniently close to the right index finger to adjust the volume level with something like :
* short press : increase volume by x%
* longer press : decrease volume by same amount.

I've no idea if it's easy or even doable but in my opinion, it would greatly improve the quality of calls.