Read a DanFoss (Siemens?) Flow meter (HART Protocol)

Yes Im aware of the physical details, its a FSK signal (0=2200hz, 1=1200hz) modulated over the clasical analog 4-20 signal.
That funtion is taken care by specific chips (CD5700, 20C12...), but I would like to discuss with someone who has worked with this before, I need the commands to demand certain mesaurements from the flow meter, handshaking...
The water flow meters datasheet doesn't provide any details on using the HART protocol with it

Thanks