Yeah, already did that.
The problem is as described earlier in this thread, that the printer presents itself via mdns and are discovered by AirGroup and stored in the AirGroup cache. While it is still in the cache, AirPrint works as it should. But after a while, the cache expires, and then AirPrint stops working for the iOS devises connected through Aruba IAP's.
And it would seam that the only way of getting the service back up and running, is by restarting the printer.
But yes, I made sure that packed filtering are disabled for the ssid, and AirGroup is enabled for AirPrint service. "deny-inter-user bridging" is also disabled. And as said before the whole thing works for about 15-20 minutes.