Zuki,
Your vocals aren't really separated, as they get summed into the QSC amp with the kb tones. With just 2 wires from the keyboard you have full control of every element of your performance. The mic has dedicated volume knobs for lead and harmony, and the KB sounds have a balance control for lead/acc. I'm still a little cloudy on why you feel you can't adjust the mic separately, right from the kb cockpit.
Thanks for the vocal compliment, BTW. Shux