Yes you will need an adapter to attach your digital back to the Cambo Ultima. You have two ways to go, one is using a "live video adapter" which is a plate that goes onto the rear standard that features just a mount for your digital back. This would require you to utilize the Live View function of your digital back. Secondly you could use a sliding back which has a ground glass and a mount. We usually sell the KaptureGroup versions of these types of adapters.
To trigger the lens you would connect a shutter release cable to it and click away, unless you are thinking of using an electronic shutter. Remember on some models of PhaseOne backs you need to wake the DB up first. There are a variety of ways to accomplish this like release the shutter, re-cock and then shoot, use a two-shot cable release which will wake the back up at the same time you release the cable, or use the special sync cable from Phase One that has a little button on the jack that you hit to wake up the camera, then you just release the shutter.
I have had clients who have had very good success with the Schneider Macro Digitar 80mm or 120mm.
I would also recommend a very sturdy tripod and head.
Lance