Alot depends on the purpose of the cable release. If you are taking long exposure tripod-mounted shots, some people use a thick elastic band or surgical tubing. You can set up the camera/tripod, cover the lens (with a hat or lenscap, etc.) slip the elastic band over the shutter release (have a loop or something under it to make this easier), then once the camera has stopped moving you remove whatever is covering the lens and replace it when the long exposure is complete, then move the elastic off the shutter release.
Others have used a custom fabricated bracket and a tradtitional mechanical cable release - drilling a hole partway through the shutter release button helps prevent the cable from slipping off.