I found out that some PPC devices like Acer 20 series extend the
ActiveSync by some additional parts - ON THE PC SIDE - not on the
Handheld side. So I am in doubt that it is RAPI.
F.i. they can call an own Sync Manager, connecting to (whatever)
internet services and so on.

I wish to do similiar (writing Windows-PC applications that are
invoked onto ActiveSync activation), but found no hint in MSDN. Did
you?