(*Newb to the Forum...)

Ok I am using a Xerox 252 Docucolor w/Fiery V: 5.3

I have a newsletter PDF file that was created in InDesign using Data Merge. The final piece needs to be 2 - 11" x 17" double sided pages folded and stitched to an 8.5" x 11" final piece for mailing flat.

One issue is the piece even if I try printing one at a time is folding backwards and for some reason I cannot seem to remedy the situation, tried multiple things. Am I missing something?..

The other issue is the PDF file that was originally created through InDesign CS5 using Variable data through Data Merge for the address list is 3,412 pages. After every 4 I need to have the pages fold and staple. How do I set this up properly? Not looking for a work around ( like setting up all 8.5" x 11" page up in the fiery to make the booklet) only interested in the proper method of doing this. I want to know the right way of setting this up. I've searched but couldn't find the full answers I was looking for.

Any help would be greatly appreciated.
-Thank You!