AO pass but with specularity

[craigdvance]

Is it possible to render an AO or dirt pass but keep the roughness or gloss values? I know I could comp this, wondering if there is an override I can use to do this in one go round.
like this example. I could do a single material override but that would make everything the same value.

[hermit.crab]

Sorry to say, there isn't such an option in Maya (we do have it in 3ds Max though). Your best bet is to render a VRayExtraTex element with VRayDirt and comp it with the reflections/specular.