What am I doing wrong in this RBI exercise?
You've got the heading right.
Now rotate the whole view of both instruments to the aircraft orientation, and you see the direction in which the Relative Bearing Indicator (RBI) points. Now it's easy to place it onto the correct position on the card.
The RBI points towards the beacon, but does so relative to the aircraft The dial with the compass in the background is not rotating automatically with the gyro compass, so unless it is manually alligned to the gyro, the top is always north.