from the user manual:
To sync your key fob to the receiver…
1. Press & Hold the on/off button on the receiver until the light on the receiver starts to flash.
2. Press & Hold the on/off button on the key fob until the light on the receiver turns constant
assuming the replacement remote is the same frequency?
I received a replacement remote from Big Foot and have been unable to sync it with the receiver following those instructions, which were the same also provided with the remote.