As a was using the N95, connecting the SU-W8 was in two steps. Firstly you need to pair the N95 and the SU-W8 in exactly the way described above. After that, you are not yet able to make any input. On the N95, you should go to a menu called connections, then choose "wireless keyboard", than choose "search for Keyboard". Once the SU-8W was found, an 'enter' ended the job, and input was possible.
So, apparently, this second step is not yet enabled in the N 900. I cannot find any "wireless keyboard" in "settings - personalisation - text input"
I am eagerly waiting for a method to join N900 and SU-8W
best regrards,
willem