So you know for next time, save a hex file of you model before export. Then you will not have to do what your doing now to get back the original size. Save often, so if you need to go back to a different starting point, you can just load a sved hex file. I somtimes have 10 or more saved file for a piece of cloth so if I don't like how something turned out I on't have to back track to far to start again.

dvlenk6 way is the proper way to do the mapping in Hex. There is a tutorial at PP that shows you how to work with the UVMapping in hex with the same type of unwrapping as what dvenk6 showed you.