Electronic Cable release trouble and 220 film back question

I'm new to the RZ67. Just purchased a ProII D and along with it an electronic cable release. After familiarizing myself with camera and shooting some polaroids, I plugged in the cable release but have not been able to get it to fire. Is there a battery inside that may need replacing? I see a tiny screw underneath the release but I'm reluctant to unscrew it without knowing what I'm doing. Also, can I use 120 film in the 220 back?

No answer for the electronic cable release, but I don't recommend shooting 120 film in a 220 back. I tried it as a test and got bad results. The images looked like the subject was moving even though the camera was mounted on a tripod and shutter tripped with a shutter release cable.