I was wondering if I could build my own remote.
At the end of the day all you're trying to do is wireless activate a 12V wire which in return activates a relay.
So why couldn't you use something like this:
DC12V 4CH PR Wireless 4 Channel Remote Control Switch Stepper Relay Switch Case | eBay
Buttons A and B could be set up to lock and unlock the door; buttons C and D could be setup to lock and unlock the compartments.
The downside is the keypad wouldn't work, and the other things like the lights wouldn't be controlled, but other than that, why wouldn't it work?