I have the Diamond too, but a N770 OS2006. I have tried to connect both with Bluetooth, but without success. First connection was established without problems and the Diamond was detected as a dial-up device (my Diamond has DUN as available profiles, don't know about), but without file transfer or SIM access.
Well, I have activated SIM access and FTP / file transfer then but now the N770 can't connect to the Diamond anymore. Every try is canceld with the message there are no useable Bluetooth protocols available. Strange!

Regards,
Frank