Here's what i do to my Polaroid cameras (assuming you have one of the older style cameras that has the door on the back, directly beside the film door):
*Go to Radio Shack and buy a 2XAAA battery holder for 99cents.
*Snip out the plastic inside the battery compartment (keep dry-fitting the holder until you get a good fit). Leave the metal piece, it's what keeps the door shut. (I used heavy-duty wire snippers for this job)
*Snip off the battery snaps and strip the ends of the wires
*Hot-glue the battery holder in place (this is optional, but I recommend doing so).
*Snip off the excess battery holder wiring and strip the ends of the wires.
*(Optional) Put heat-shrink tubing on the ends of one of each of the battery holder wires
*Solder the black wire from the camera to the black wire from the battery holder, and the white to the red.
*Insert batteries and test the shutter. If it doesn't work, probably didn't get a good connection when soldering, or you put the batteries in the wrong places. If neither, try brand new, out of the package batteries.
I've done this to 3 Land Cameras and they all work great. There's no way to tell they've been modded unless you open the battery door.