[C210N]

I can't accept that any engine performance data transmitted... would include ... location, course or direction...

I would expect it to. These aircraft have a web network of interconnected busses that would have lat/lon and ground speed info. These busses are ARINC 429 busses, and are akin to CANBUS on cars. When transmitting engine data, it would naturally have identifying information with it to help correlate with other data streams, which would include timestamps and lat/lon. Lat/lon on these reports would be almost certainly present.

[Bobalu]

Yup, a helluva lot of info is available on the ARINC 429 avionics bus. You could pick off whatever you wanted and relay it to a satellite in a hurry.

Hobbyists build cockpit replicas using old instruments connected to a computer using the ARINC 429 bus...you can handle the data with a simple ARINC port adapter. Or you can whip up a simple adapter on your own using a micro-controller.