I've some .resw files for some languages translated in the past placed in Strings folder of Shared project.
Now I've added new texts to the default language and want to have them in other languages too. I enable multilingual app toolkit from Tools menu. it creates some files in Windows Phone Project.
But when I disable multilingual toolkit it doesn't generate usable .resw files for selected languages. It even doesn't use existing translations.
Does Multilingual App Toolkit support Windows Runtime apps?
It depends on the version of the Multilingual App Toolkit (MAT) that you are using.
MAT v3.x does not create the target language .RESW files. It stores all the translation information in the XLIFF (.xlf) files and calls the MAKEPRI.EXE process directly to add all the translation to the .PRI file. (Be sure you are running the latest version - 3.1.1250.0 as of today). Additionally for Universal projects each project (Store & Phone) need to be enabled separately, but does handle the resources in the shared project. This allows for form-factor based translations, but is not intuitive since the translations live in the specific project and the original resources live in the shared project.
MAT v4.0, which is a technical preview release, does create the target language .RESW files. The technical preview focused on Xamarin support initially. Universal app support is still limited and does not support resources in the shared project. This is coming, but not fully functional. If using v4.0 TP, you will need to move the resource outside of the shared project before MAT will see them.