Ski Pass Through - How to open it?

[bbschreiber]

I have a 2004 330xi with the winter package. I have occasionally tried and failed to figure out how to open the trunk side panel of the ski pass thru. Supposedly there is a latch somewhere, but I have not found it. There is a black knob on the trunk side of the seat, but it does not seem to do anything. The owners manual is silent on this feature.

Help would be appreciated.