I finished the work on a site (REFULOG) and I generated the .resx files for every page (Tools/Generate Local Resource; Make sure you are in design or split mode, otherwise the menu item does not appear).
After this I tested the app called Resx Crunch (It is about to come out.) I loaded all the generated .resx files, added the desired languages, made the application copy the values from the default .resx files, so at the end it looked like this:
Default value | DE | ES
-------------------------------
apple |apple | apple
...
I saved the info as a CSV file and I sent it to the translator. When it came back from the translator:
Default value | DE | ES
-------------------------------
apple |Appfel | Manzana
...
I loaded it, Saved As into the application folder, and that was it.
I tried to use other localization tools, but they wante3d to do too much and could not do enough.
So to answer your question: Generate the meta tags & .resx files using Visual Studio and do the translation using some localization tool.