B-Vent for wood burning heat zone

I had this thread on here for several days but just noticed somehow it ended up in the gas forum.I am still in the process of hooking up my Quadrafire 7100 I bought from a co-worker.It came with two heat zone kits,At least some of the kits. The manual says to use 6" B-Vent only. The kit came with adapter plates that mounted on top of the fireplace box and the B-vent hooks to that and you run B-Vent to the room you want to heat and the blower assy mounts in the wall and the B-Vent hooks to that.. He doesn't have those adapters anymore that mount to the fireplace and I cant find them anyplace.I have searched and searched. Anything else I can use? Anyone have one laying around or know where one can be found?
Here is the heat zone manual for the kit.You can see the adapter I am looking for.
http://www.google.com/url?sa=t&rct=...sg=AFQjCNEA1ZpDMESt8kpTGkk2-3gPzIdcYw&cad=rja

I also called my local fireplace store(HMI Fireplace) and he told me I couldn't just order the adapter pipe, I would have to order the whole kit for almost $300.