Envisalink 3 Vista 20p mounting adapter

I recently purchased a Honeywall/Adempco Vista 20p security system and an Envisalink 3 module to connect it to my network. The Envisalink 3 comes with 3 mounting pegs to mount it to the Vista enclosure. Unfortunately, the enclosure I received seems to be a different model from what the envisalink was designed for, and no holes lined up. I could have drilled new ones, but didn't want to deal with metal shavings, or sharp-edged holes. And if I had been off by just a little with one hole, I'd h