I don't know about your shutters, but if I am out in the boonies and have lost my cable release I just tie a piece of thread (actually several twirled together) to the shutter release lever. Works in a pinch, but kind of useless for time exposures. I make this little thread release about 10 inches long. Actually you could use it for time exp's by tying something heavy enough to it to keep the shutter tripped during the exposure. That way your shaky hand won't transmit any shake to the camera. Lack of wind would be a necessity!

Just call me the Inspector Gadget of LF LOL!