altering brembo calipers?

[bugsoup]

Has anyone ever modified a caliper by machining a little off the outside (the surface closest to the wheel)?

Background: I have 996 front and rear brakes (calipers and rotors) and 16x6, 16x8 Design 90's. The rear setup should be fairly simple to fit, but the mockup of the front is giving me problems. On the oustide surface of the calipers, there is a step that increases the overall outside diameter to interfere slightly (maybe 1/16") with the inside of the wheel. The wheel's inner most material also happens to be a stepped to the inside towards the caliper.

Is it possible or safe to remove a bit of material from either the wheel or caliper to make them fit together? I am going to try to get some pictures to further explain the situation. In the meantime, if someone has understood my explaination or has done this, I'd be glad to hear what you have.