Step 1: The Set-Up
Now I had thought the easiest would be to just make a fitting flat-head driver and try that, but it didn't work. In the end it was quickest to just make a complete 5-wing Torx.
I didn't take pictures back then, and the original remained with my friend, so I wanted to see if that was just dumb luck, or if the result could be recreated. I got some gadgets from a Flea market today, among which an Ipaq with dead battery, and a bluetooth gps dongle. These have some screws which are slightly smaller than the smallest bits I've got in my toolbox, so I gave it a try. So
(BTW, the camera is from the same flea market, so I'm trying that out at the same time... Excuse the image quality.)