Auc, to tell the truth I have never made vegetarian bigos myself. But I guess it's almost the same way as the normal one. Just instead of meat you put soya:)
Here is the recipe for bigos with meat:
http://www.bellaonline.com/articles/art43070.asp In vegetarian version you change meat and sausage for dry soya balls (small ones). But I usually keep them in a vegetable bulion for a while.
The cabbage is made the same way as in the recipe above. Of course soya does not provide the flavour that meat does:) and probably it would need more spices too (as dry soya does not have them naturally as sausage do).
Next time I eat vegetarian bigos in this wonderful vegetarian bar I'll take a photo... apart from this I will try to prepare one myself:)