FMC640 can not send back any data to the CAN bus.
But it has an option in RS232 to send the records to external device. It's called Rec to LCD.
Device will send the record in ASCII format through RS232, this record has Lat & Lon Coordinates.
If you can use any RS232 to CAN bus converter which has an option to configure the ASCII values, you will get the GPS data in your CAN bus.
Thanks in advance,