Irssi core bugs

Trying to implement a push-aware bouncer (http://colloquy.mobi/bouncers.html) for colloquy mobile (CM) as an Irssi perl script, I ran in the following problem:

CM sends (non std) PUSH irc messages to tell the bouncer about the device information, so:
* bouncer has to be able to intercept them
* bouncer should not forward them to the actual server

Once proxy handles the command its way through handle_client_cmd(), it passes unhandled messages (including PUSH) directly to irc_send_cmd(). AFAIK this does not emit any signal. So we cant see/filter PUSH messages.
I hope I didn't miss another signal.

For the code posted in http://static.ssji.net/colloquy_push.pl.txt, I added the attached patch to filter just PUSH messages, but I assume this could be transformed in a broader way to intercept client trafic.