LanC A/M Focus and "Mode" commands for TRV950

[subpilot]

I am constructing a LanC control for a TRV950 DV Cam. I can get the "normal" LanC functions to work that use bytes 0 and 1 but can not get either the Auto/Man Focus toggle function or the "Mode" function (Camera,VCR or Picture Mode select) to work . I suspect that those commands need to insert bits in bytes 2 & 3. The LanC spec claims the A/M Focus command is 28 41 but this does not seem to work. I have heard that there is an expanded spec but have not been able to get it through Sony or any other source that I can find.
Any clues?