Sorry for the late reply. Got sidetracked by ordinary life. Really appreciate your offer to help out Simon.
Problem with the original key seems to be that it jam inside the narrow slot cut between the two edge contact pins on the voice card PCB. Combined with the hooks does not align and lock at 90 degree as intended it slips out when the card is removed. As it is nearly impossible to mount the key without disassembling several voice cards or remove the case lid end user just through out the key.
My thinking is if the key assembly where taller the hock would have better potential to hold the key i place if it get sucked to the PCB.
Image with some measurements: http://snw.lonningdal.no/sds7/sds7_key/key_metric.jpg
Directory with all the image files: http://snw.lonningdal.no/sds7/sds7_key/
Link to zip file with all images 3,7MB: http://snw.lonningdal.no/sds7/sds7_key/sds7_key_images.zip
best
-h