/diy/ - Do It Yourself

I have a noob question. I'm trying to add a 2-channel remote to an automatic gate opening system. The system supports multiple remotes (up to 8) and lets you program what button activates what function. Rather than buying an original keyfob for 50 bucks, I cheaped out and got one for 6 bucks. Both the original keyfobs as my cheap one work on the same frequency, 433 MHz, but I doesn't seem like the system detects the cheap one when I try to program it into the system. I already tried erasing all keyfobs and adding them again one by one, but the system only recognizes the originals.
Am I shit out of luck and is the system more complex than I thought, or is there something else I could try?