Thanks for the welcome!
I enabled every Java option that I saw in the browser options pages.
Now, I can get a little bit further!
After I click the "Launch Chat" button, the blue progress bar shows that my berry is trying to run a script.
Once the script has apparently loaded, I am left with a white screen. Nothing to respond to my customer with...
Maybe it's possible that I need a new berry or wm6 phone that has better browsing capabilities. That would really stink, I like this phone!