You should probably set the channel to be secret, meaing it will not show up in a channel listing:
/mode #YourChannelName +s
Now for the real trick: You can password-protect your channel, so that a user must use that password when joining the channel.
/mode #YourChannelName +k YourChannelPassword
(Note: You can reverse any of these settings later by changing the + to -.)
This sets a password for your channel. Now, to make the hack work with a password-protected channel, you need to add a parameter to the template. Somewhere in the "param" list, add this:
<param name="DisplayConfigChannelPass" value="true">
Also, make sure that you have this line in there, too:
<param name="DirectStart" value="false">
This will make sure the config screen, which asks for the password, is shown. Note that you have not seen this screen on my site, because I have it bypassed.
Look here for a complete list of the various parameters you can set through the template:
http://www.jpilot.com/java/irc/manual.html By setting various parameters, you can show the config screen, but block it from showing the channel or server info, which will help keep that info secret, making it harder for people to break in.
You just need to tell the people who need to know it what the password is. Note that they can still join through mIRC or other separate programs, by using this command:
/join #YourChannelName YourChannelPass
Note: I have not tried all of this stuff myself. It's all from what I've read here: http://www.jpilot.com/java/irc/manual.html and here: http://www.newircusers.com/ircmds.html I think this is about as secure as you can make IRC, from what I can tell.