Took a long time to get this locking clip in. I tried just chiseling away the wood and have the solenoid latch to the wood but that didn't work so well. I made the clip but it was very hard to screw it in. The space is very tight and I didn't have a way to pre-drill. It came out a bit crooked but works.
Only downside is that the solenoid needs to be retracted before you can lock the box. That can be done with a finger or through a command.