Unless you make your FAQ under 300 words, it can't go at the end of a chapter either. Sorry!
And, you're right, you could not make it a separate chapter either.
The only place I can see posting an FAQ would be on your profile in the "Main" section. You could also post it on the forum under "Self-Promotion" and include a link to one or the other at the end of the chapter.
OR
You could just answer questions as they arise?
I dunno... I do know that our rules make it difficult to do things like that, but the primary thought was that such things should be explained in some fashion in the course of the story, rather than being posted as stand-alone notes. The only exceptions we make for overly long author's notes is in the case of historical information or - as you mentioned - technical information that increases the readers' knowledge of events referred to in the story.
~~Wiccan~~