Ok, I tested now on the test-server.
Write my experience here for you who wonder yourself:
I have Wp lasest installed
I had installed and tested bbPress 2.1 the last week
I now installed BuddyPress as a plugin and did the installation without activating the forum.
Then did go back to the BP settings and activated site wide forums. Then voilá the forum was integrated part of BuddyPress.
Way to go!
What theme did you use for your 2.1 install? What modifications did you make to the theme if any?
I had built my own theme, but when installing the BuddyPress I did choose to use the default BuddyPress theme.
I will probably edit my theme to work with BuddyPress. It says that I can go through a step by step edit of my theme, so I will try that
Right now I am wrestling the fact that I can not get it into my language. Yet…