Vintage Omega de Ville 115.0001 case ring needed

Hello. I have a vintage Omega de Ville case and 625 movement. I am unable to make a watch out of them because someone gave me the case without its inner support ring. I attach photos with both of them. It is the ring that holds the movement that I need.
I think I've searched everywhere, ebay, amazon, sites from my home country etc, but was unable to find this spare. Does anyone have this piece, or knows where I can find it?
Many thanks!