Zhenya, you might try replacing the broken pin with music wire. It should be available in a variety of sizes from model building suppliers (used for lots of stuff in model airplanes and similar), and as it is cold-drawn carbon steel, it is very hard and stiff and extremely strong for its size. I used it to repair (replace, really) the firing pin in a pistol some fifteen years ago; still have the pistol, and the repaired firing pin is still fine (and it takes a lot more stress than anything inside a camera).

Don't try to cut the stuff with cutting pliers, though; you'll notch the jaws. Instead, either notch it with a file or grinding stone and snap it over a hard edge (like cutting glass rod or tube), or cut it with an abrasive cutter like a cutoff wheel in a rotary tool. It can be soft soldered (electronic or plumbing solder) without detempering, if the work is done carefully to avoid applying more heat than absolutely necessary to melt the solder. I think you'll find it more than adquate for the part you describe...