Now, now, let's not argue! Nortel has provisioned the "Activity Code" so that you can apply it to actual activity (i.e., logged in and at work on a call) as well as Not Ready due to customer demand. Some 3rd party applications may not have been able/felt it was not important to allow activity codes to apply to not ready time. That still doesn't answer markus115's original question.
So, markus115 -- your report does show activity codes (it shows the default, at least). What release and patch level are you at on your server and client(s) involved? Also, can you verify that your phones and PBX database are configured to correctly recognize activity codes (clue: is there an audible sound that even the callers can hear, when codes are entered)? At the surface, it looks like the system is not seeing any activity codes being entered.
Can you set up a test to get that determined? (And don't fuss at me, we're working to fix your problem here)