brconfig hates me

[the p0pe <rewt_(_at_)_eghetto_(_dot_)_ca>]

Hi. Recently i decided to upgrade my companys vpn setup from vtun to ipsec
+ bridging, because vtun has not scaled well. Anyway, I have the ipsec
links up and running no problem, but whenever i try to run 'brconfig
bridge0 add [encX | gifX] i get the error 'brconfig: bridge0: [gifX |
encX]: Invalid argument'. The gif interface is setup fine and works, but i
have doubts on the enc interface, as i haven't found too much (actually,
any, apart from the ifconfig source, the man pages seem to be in need of
updating) documentation on how to assigna an enc interface to a SA.
Now, i've read the FAQ and man pages, and even gone through the bridge
part of src/sys and the source for brconfig and ifconfig. i'm stumped, but
i have a feeling that it's just me being dumb and missing something so
obvious, that when i find out, it's going to hurt.
Any help would be appreciated.
Jonathan