Your work is some of the finest I have ever seen for the phpBB venue. I am currently using this one as a Ragnarok Online Guild Forum for a server I play on.
When the server crashes our Forum participation rises (funny thing, eh?). I have looked into a live Chat MOD and found a couple that are not invasive in their implimentation but after looking at your template I decided against fooling with it. -- I'll do without rather than risk harming the integrity of your work.
Can you recommend a suitable mod that is not going to thrash your template? I am a pretty decent developer but I do not have the time to investigate this thoroughly -- or risk stepping on your license.