i have never say the server address use / or \ chars, but in the connection dialog, you can tell the server with a private name return by $network, and this same name is used in the path of the logfile (with default setup).
i have choose voila/wanadoo because the server "voila" irc.voila.fr is linked to "wanadoo" irc.wanadoo.fr (and other address)
My problem is the same of
sais : Sais have find a problem with the logfilename (: between server and proxy) and me with / in networkname.