Actually if you want to convert a piece of clothing from M3 to V3 you might want to use the Clothing Converter, because you actually want to change the shape of the model, to use with a female character, and you can't really do that with the Tailor (unless you're converting it for use with the V3 Male character).

What problems are you having with the Clothing Converter?

Ask me a question, and I'll give you an answer.