Am I to understand the ground wire is unconnected to the pot Icenor?
If this is true, you have succeeded in introducing a resistance in the signal path, but technically not an attenuator. This may be sufficient but the chances are good that it will not be for your camera input.
To act as an attenuator lug #1 should be the input (from the audio panel) #2 the output (to the camera mic input) and #3 then the ground.
good luck!
edit: this illustrates the concept. The battery, on the left represents the output of your audio panel while the V (voltmeter) on the right is the intended camera input.
