Anyone who is curious about .cr2 anatomy and function might find this link valuable, the writer here does a nice job explaining such matters clearly...

http://brian-the-techie.blogspot.com/2013/04/how-to-poser-rigging-tricks.html?m=1

Thanks for this link, DM.  He is very, very good at explaining this stuff in plain english.  Sometimes, I read Poser stuff and they might as well be speaking a foreign language.

Spending time reading through it.