Sure. GotWoot and most likely other groups wouldn't have a problem with using their releases to translate into Vietnamese. It is a common practice to re-encode people's releases or use their softsubbed translations for one's own group.

It's a good thing that you're doing. Your website is cute!

Ah! My Goddess raw here found via NyaaTorrents.

If you can't find a raw you can always just mux out the subs of someone elses release and cut in a raw OP/ED you find from somewhere, that requires someone who knows how to manipulate video (like an encoder).