After reading
this thread I tried shorting the data pin on the lens side of the TC. This resulted in the following changes to the behavior described above with the DA* 200:
menu, info, and Fn buttons now work
indicated aperture is two stops slower than actual setting (range shown is 5.6 to 32, resulting in actual aperture settings of 2.8 to 22).
metering off, but consistently so -- despite indicating smaller than actual aperture, selected shutter speed in Av mode is faster, resulting in about one stop underexposure
Interesting. Anyone have suggestions on different approaches to this? This is just guesswork for me.