ZRE Translation Toolkit: importing multiple languages?

[Ross Presser]

I just downloaded this to try it out, and it's not making sense to me. The import dialog only allows you to import one language at a time; but if you do that once, then try to import a second language, all of the strings from the second language appear as their own rows in the grid.  There's no attempt to match up the strings by their resource key. How can you import multiple languages from .NET resx files in this way?