can I use an accessory viewfinder with a digicam?

OK, kind of an obscure, technical question but I know we have several photography-savvy 'dopers so I’m giving it a shot.
So I’m looking at getting a digicam for street/lightweight shooting. I’m used to a DSLR, so at the moment I’m favouring the sony DSC-V3, as it has a reputation for low shutter lag. Trouble is, I don’t like using an LCD and the optical viewfinder looks poor. Is there any reason I can’t just buy a Voigtlander 50mm viewfinder, stick it in the hotshoe, zoom the lens to 50mm and snap away? Has anyone done this?
I’m assuming my question has a yes/no answer but am aware that if could also possibly be a IMHO. Any insights appreciated.

pd

I don’t see why it wouldn’t work fine. You might want to check to alignment between the aux finder and the cameras lens. I’d suspect the alignment of the hotshoe might not be that accurate. But at any reasonable distance it’s probably as accurate as it needs to be.