You can also just use a strip of electrical tape across the underside of the drive cage covering the screws to help secure them. If you run the tape so that it covers the edges of the drive cage as well this has the added benefit of keeping the rather sharp trailing edge of the drive cage from slowly cutting through the cabling at the back of the empeg. I had the insulation nearly worn off a 12v lead on one of my empegs the first time I opened it up due to rubbing against the drive cage!

-Mike