Yes, it cannot do that, there is no API that would allow it.
For Poser8 I do not know, I just recently bought it, hoping for the hierarchy editor to allow set up of the ERC.
To give an update, we had a problem with shading errors on body part seams, this is now hopefully fixed and about to be re-tested. If its finally ok, then I will do a final review/regression test, write a better manual and submit it to rendo and pray ;).