re: Now you know what to use: openEXR.

Actually, I do not own Poser Pro, so... my "workaround" is to either:

a) do the entire animation in Lightwave and/or Motionbuilder, with UV pass mapped onto 3D geometry and rendered separately from the "main" animation.

b) Use Poser 7 to do the character animations that I'd rather do there (than in Lightwave), and then do the UV pass in Fusion 5 (a compositing package) where I am basically hand-teasing the UV pass to visually integrate with the rendered animation. 

Option B is what I used for the "contemplate this" title, which is quite crude, and I know I can do better. It's 6 of 1, half a dozen of the other, in terms of which method to use.