Hello to All,

OK so, I've gotten stuck with a tile project that is a bit more intensive than any I've done before. I'm having to tile a large shower stall that has been hotmopped flush to the studs and I've never tiled over a shower floor before, just walls, countertops, kitchen & bath floors, etc.
I hear words like "drypack" but I'm having a hard time finding a step by step process anywhere. I have had 1/2"denshield tile backer installed on the walls overlapping the hotmopped area by at least a couple inches. This leaves me needing to either build out or float out 1/2" to match the tilebacker surface. What exactly would I float or build this out with? I can't find a thinset that says that it can be applied in this manner or will adhere to this hotmopped surface.
Part of me wants to just build it out with 1/2" hardibacker to make my wall surfaces flush, then, while I'm at it, put the hardibacker on the hotmopped floor (thinset below it, of course) then tile it as I usually do. With the addition of a few small stones near the weep holes, it would be a done deal, right?
What bothers me about this method is that I would be penetrating the hotmop with my hardibacker screws. Even though I know that the hardibacker method IS waterproofing, it seems to negate the whole hotmopping process... or does it?
Of course I want the easy way out, but, more importantly, I want to know how to do this the right way as well.

Can anyone share their well appreciated experience with these matters?

Thanks for your time!