Have you contacted Chris Sherlock for a possible repair? He's in NZ and he just worked on a Voigtlander Vito II for me. He mostly works on Kodak Retinas but I've I've also sent him a Voigtlander Bessa L in the past. His work is top notch.
Nice catch with your Voigtlander Vito III, maybe someday I'll get one.