How can I make this permanent?
As I said, put the .bls file into the .zip folder. Then you have to add some lines of code to the .MIS file that execute the .bls file when the host first connects to the server. Unfortunately, I don't think there's any other way than when the host connects, so if you make a dedicated server using the map it may load the save multiple times, although that won't change anything if you don't delete the bricks.
This is what Boom told me.