How can I remove the glass from my Bosch Extractor Hood DWA09W451B?

We wish to decorate the walls in our kitchen, on one wall we have the Bosch Extractor Hood which has a glass panel. This panel is tight against the wall, therefore we wish to remove it. From a Bosch Spare Parts diagram it is clear the panel is held in place by two plastic clips (one either side). However it is not clear how these clips retain the glass, therefore we are not sure how to remove them. We would prefer not to damage them and certainly not the glass panel. Has anyone any idea how to remove the retaining clips?
P.S. I have contacted Bosch UK twice and have not received a satisfactory response.

Dave Bass
November 2012