Need some help with CAN signal pairing between different generations...

Current bench test setup:
- 1K0 gateway (1K0907530C) from VW MK5. Obviously it has Convenience and Diagnostic CAN buses. Other ones doesn't matter now.
- Parking aid ECU from Audi A6 C5. It has K2 line for diagnostics and Convenience CAN as shown in Elsa diagrams. A6 C5 facelift instrument cluster acts as "gateway" just like on newer cars. But because of instrument cluster is so bulky I'd like to wake up parking aid ECU with some real gateway which is many times smaller in size.

I can connect gateway with VCDS, but parkings doesn't want to open a connection to K2.
Parking aid ECU is ok, was tested in real A6 C5 car.
Tried with parkings checked in installation list and unchecked. Didn't help either way.
Wiring rechecked multiple times.

Voltages on convenience CAN-H = (0.25V ... 0.32V changing) and CAN-L = (4.64V ... 4.75V changing) with parking ECU connected (don't have a scope for now, but analogue multimeter shows it).
Voltages on convenience CAN-H = (2.53V) and CAN-L = (2.46V) with everything disconnected (except gateway itself).

Isn't it possible?