Canbus trouble - Alpine ILX-700

[Carstenbn]

Hi all
I'm hoping that someone can guide me to the solution to this problem.:
I have bought a preowned Alpine ILX-700 Radio, including canbus interface and cable harness.
My previous radio was a RCD-310, and the Parking Assist was working splendid
After mounting the new Alpine Radio, im having problems with the parking assist.
Sometimes everything is fine, and the parking sensor is working.
A lot of times when i start the VW - the icons for parking assist doesn't show on the Alpine display.
It looks like the Radio doesn't know that the parking sensor system is present in the car.
The parking sensor is still working fine as an accustic device - but nothing on the screen.
The rest of the canbus stuff is working fine all the time - i can controle radio and telephone etc.
I got some help from Alpine in denmark, who sent me a new interface for the canbus (APF-X100vW).
But this didn't fix the issue.
Anyone knowing anything about canbus - can this be some programming of the canbus, telling the car that the radio has parking assist ?
Or do you think its more of a defective radio headunit ?
Hoping for some nice clever words
Best regards
Carsten