I have an FHT8W and looking in the instruction manual it doesn't say that it works with the HomeMatic system.
It specifies that it communicates with all control units within the FHT system, i.e. "FHT 8R", "FHT 8B", "FHT 80B" and "FHZ1000" and with the valve drives "FHT 8S" and "FHT 8V".
I have had a look on the HomeMatic site and can't find any equivalent of the FHT8W which IMO is an essential part of the system for effective operation. It would be odd if they didn't do an equivalent product though.