oh, I meant that you may have needed to drop a wireless NIC into the client machine with which you'd web-gui into the soekris board that had it's own wireless built in, but..I guess that's not an issue.
in any event, are you feeling man enough to do an XML rewrite by hand and then drop it into your monowall install?
and if it turns out ....for whatever reason (i'd be amazed) that monowall was infact not built to function as a WAP (wireless access point).....then there'd be no way to set a SSID......but I'm pretty sure that monowall can function as an Access Point....I'd almost bet on it.
try searching around in the config XML file for "ssid" and see if anything comes back.
also, don't forget to check out the "diagnostic" area in the web-gui menu. If I'm not mistaken, there's a wireless thing that shows up in there when the right hardware is present.
******edit******
http://m0n0.ch/wall/images/screens/interfaces_wlan.pngBoom-Shakalaka