This is a known bug that e-on are aware of but I'm sure it was fixed in SR1!
Your problem I have had, it doesn't seem to be a Poser issue though and I have been unable to replicate it after the first service release, I take it you have tried that!!

Sometimes, before SR1 this could be "fixed" by exiting Vue, restarting it and importing again, but not every time!
Vue imports Poser materials just fine, I never have to alter my Poser imports, it does however have serious issues with poser shaders at the moment, again this is something e-on and Smith micro are working on and this is a Poser problem rather than a Vue one!

Injustice will be avenged.
Cofiwch Dryweryn.