I just had the same problem. Open the top panel by unscrewing the two screws at the back.(Note you need to pull the two plastic flaps that the screws were in towards you before lifting up as they have bits of plastic which go into the frame.
Once you have the top off look for the latch. Little black plastic with blue wires going into it. I know, does not look like a manual latch, but if you put you hand under the whole thing an pull up you should head a little click and the door will open.
GB, November 2010
