This is not possible AFAIK. In the Obex protocol there is something called a Capability object that might contain this information, but it has not been tested if this object is even available on cell phones as the Obex protocol is originally provided for infrared services.
The Obex components provided with BlueTools do not offer any way of retrieving this object. If you want to attempt to retrieve you must contruct your own Obex client implementation. The Obex protocol is available here: http://www.irda.org/