After Sinnerman's help I thought I had this figured out ... but apparently not. That is I still don't believe I have iTunes configured properly for allowing MC17 to export direct to my iPhone 4 (iOS5), and possibly JRiver hasn't yet quite anticipated the proper iTunes (10.5.1) configuration, or provided us with the instructions ...
As is, I can only get MC17 to add songs, and it refuses to sync in the sense of removing tracks not visible in the selected playlist. I was hoping I could disable "Sync Music" in iTunes and use MC17 for syncing direct (as direct as it can be, but still via the iTunes SDK (which must be a moving target for JRiver). However, I still cannot get MC17 to export to the iPhone, even when "Sync MUsic" is enabled in iTunes ...
The best I can come up with and use dependably, is to re-enable "Sync Music" in iTunes, ... have MC17 write to an iTunes playlist ... and then sync my iPhone via iTunes.
Because I still believe I'm missing something, it would be good to hear from JRiver regarding just how they imagined this working.
EDIT: I see that MC17 is using the conversion cache for this without really converting anything. Does this mean we'll soon be able to convert our high bit-rate tracks to something appropriate for mobile headphones and allowing for our iPods to hold more tracks? ... I hope so
Another small bug I'm experiencing is that I cannot listen to music while this export process is running ... i.e., MC will not move to the next track in the playlist ...
TIA