GE Spacemaker Door Handle part number and how to replace

Hi

We have a GE Spacemaker 1400 XL Microwave oven which has a broken door handle. However I cant find the part number for this anywhere. Would anyone know what the part number is and also advise how I can change this door handle. I cant see the screws and I cant find a blown up diagram of the microwave on the GE website or anywhere else. If you have ideas on where I could order the door handle from, that would be great too. Your help would be much appreciated. Thanks