raw 396:[color:red]match text[/color]:{
;commands to execute once your hostmask is 'hidden'
}
Match text being the message given that indicates your host was succesfully changed. For example on the Quakenet network, the message is something like this:
*.users.quakenet.org is now your hidden host
Where * is the person's username.
So, using that as an example I would use the following:
raw 396:* is now your hidden host:{
join #MyChannel
}