The FD-1 Hihat control pedal is included with the TD-07KV and TD-07DMK kits. If your FD-1 is malfunctioning or has been damaged, you can contact your local Roland Service partner to have it repaired.
Rather than service, you can also consider replacing the FD-1 with the Roland FD-8 or FD-9. Either pedal would be compatible with the TD-07.
The VH-10 or VH-11 Hihat pads would also be compatible, however they need to be mounted to an acoustic Hihat stand.