I made tests and you can just open DCS\Scripts\UI\BriefingDialog.lua (with Notepad++) just comment line 192 you must have this: -- setPause(true)
Seems to work for me, i made mod OvGME ready
No Pause Briefing.zip
Had the same last time I tried it, and using mod manager is essential because you have to uninstall mod before updates. DCS will download original files and erase the mod with every update. For shelter you have a mod for textures or find original one and include it in the mod