How to remove caliper boot?

[davepl]

I'm about to rebuild a set of '72 3/4-ton front brake calipers, and I've got the piston out but the whole setup is a little different than what I'm accustomed to.

How do you get the piston "dust boot" off? I don't mean the square cut seal, I mean the boot that protects it from dust and moisture. Normally I've seen there's a "boot ring" around the outside that holds it on, but in this case it looks like it's pressed in with a metal ring.

But since I don't know for sure, I don't want to start driving out unrepairable pieces of my caliper!

Thanks,
Dave