One thing I did with my Steam SH5 install was immediately after I got it installed and let Steam do any updates, I copied all of the files inside the SH5 folder and pasted them into a new folder that I named "TWoS", since I was going to install the mod in that copy. I then added the SH5.exe to the Steam Start menu (and changed the shortcut's name to "TWoS") so that it would update its "license" via Steam when I played. I then did my TWoS install.
So I ended up with
"C:\Games / Steam / SteamApps / common / Silent Hunter 5 /"and
"C:\Games / Steam / SteamApps / common / TWoS /"
both with identical files, until the TWoS installation is performed in the TWoS folder copy...
