I've never worked on brake interrupters, But my guess is that you'll either have to remove both the brifters and interrupters together with them attached by cable, or uncable the brakes. If your bars are a different size and the brifters and interrupters need to be a different distance apart, then you will have to change the cable housing. I'm really just guessing here, but is should be obvious when you untape the bars.
Oil is good, grease is better.
2007 Peter Mooney w/S&S couplers/Terry Butterfly
1993 Bridgestone MB-3/Avocet O2 Air 40W
1980 Columbus Frame with 1970 Campy parts
1954 Raleigh 3-speed/Brooks B72