Duratrax is just rabadged futaba so this wire will work.
http://www3.towerhobbies.com/cgi-bin...&I=LXH356&P=ML If you read it is is made for the FM radios so you will not have any issues using this because like i said the duratrax is futaba with the name duratrax on it. Also that white rubberish stuff is probably a anti corrosive that will need to be put back on after you replace the antenna. I would solder the new antenna to the board directly for best reception.