I think one of the hardest things to get is that you MUST have ssl configured, and it listens on the same port(8300) as does regular messenger.
here are the instructions that work pretty well.
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If you ever wanted to use a 3rd party messenger system, like GAIM, or wanted to use messenger from anywhere OUTSIDE of your LAN, you need to do this.
Trust me, this is pretty easy, the second time.
The first time it took me about 15 minutes to go all the way through. Now, when I set these up, it is a matter of minutes.
The only gotcha in this is if you want to use an outside minted certificate. No need, but some people are anal that way.
Tom