Here's a great book I recommend on the deep workings of Poser:
http://www.amazon.com/Practical-Poser-Graphics-Denise-Tyler/dp/1584504439/ref=pd_bbs_sr_1/103-9849744-2618237?ie=UTF8&s=books&qid=1190209596&sr=1-1
(I'm not sure if the v7 book is any better than this one from the reviews - I opt'd not to get the v7 book after I upgraded to v7...)

As long as your Moi exports are readable by Poser, this book gives great details on creating props, clothing, face room etc.

I'd answer the question myself, but my Poser usage is a little rusty and I have yet myself to get into creating custom props and objects (something which I'd like to do actually since it seems to be a great way to make some spare cash...)

Your best bet would be to ask Poser related questions on a dedicated Poser site - Daz3d.com comes to mind

Good luck!

-Will