Friend of UWVisions Jacques-Yves Phelipot has posted some photos on French forum, Le petit forum de la Photosub about the process of fitting an F.I.T. adapter for the INON 45 degree viewfinder to a Nauticam housing. Adapters are available for all Nauticam housings. The tool you see in photo 4 is the Anthis viewfinder removal tool.
Thanks Jacques-Yves for taking the time to post: