Nicely done, Xenz. I have done pretty much the same as you following your instructions: a couple VM's using Debian 5.0 with openfire installed, with the database hosted in another machine.
It works great: users see each other, messages arrive, and the caches work flawlessly.
Anyway, I wonder if step 8 is mandatory. I already noticed that the coherence-cache-config included in coherence and the one included in the plugin are completely different, but I supose that the plugin works with the xml provided with the coherence plugin, and overrides the JAR one.
I hope someone can throw in a bit of light around this.
Thanks to all for the nice work.