According to the palm website, the updated ROM "optimizes Bluetooth performance for some Motorola headsets and other car kits".
I'm not exactly sure what this means, but I'm hopeful that there is something that can be done.
[cut to William Shatner] "There must be SOMEway, SOMEway to make it work"
Seriously, if this awesome software would work with the Treo 650, that would rock my world in ways never thought possible.
I'm going to re-install PhCo and start with the Sony model and see what happens.