I was going to post they are pretty much the same until it hit me that only the external connector (i.e. the large din plug) is the same. Sadly I didn't take pics of my AT's innards when it was still completely connected. Don't know by heart where the 5th wire leads.
What you need most of all is a complete F AT cable, a multi-tester (preferably with crocodile clips), a needle, pen and paper to make a pin-out diagram of the cable (i.e. a diagram that describes which pin on the round DIN connector maps to a hole in the rectangular Berg connector).
In the end, you will still need to solder a cable to the short strips of wires stuck in the connector or fill a new Berg connector.
I would actually recommend to use an XT cord instead of a model M SDL cable, this way you can reuse its rubber "cable foot" which juts out of the keyboard. If not, you will have to improvise.