Bumpmap/Displacement Map using TouchPaint

[dondi]

I am playing around with the TouchPaint node and I am trying to come up with a specific effect where I'd like the TouchPaint node to create Black & White values that I can use to displace a texture to make it look as if you are drawing in the sand (using a sand texture) as a bump map. I have tried several ways, my latest is attached, but I am not satisfied with the results. It looks like my alpha (black & white) values are inversed and instead of the touchpaint results displacing "down", it seems I am getting the opposite, looking as if the displacement is "up". Any feedback/helpful hints would be appreciated.

Thanks,
-- D