Legal Queue Names?

Does anyone have a list of legal queue characters for RT3?

I’ve been fighting getting RT3 installed on a RedHat 7.2
system and while I did get it working, I hit on an issue
with queue names.

The problem isn’t in RT3 but in the support for e-mail.
The problem was that smrsh in RedHat choked on “&” as part
of the queue name. (And I think some of the quoting too)

So does anyone have a list of characters to avoid in
queue names? And has anyone else seen this problem
on other linux distros?