I use a military ice pack vest for my Vader and it works well. Keeps me chilled for about an hour. Doing the same thing for my Biker Scout. Should work with a TK too. It is similar to this product.
http://www.polarproducts.com/polarshop/pc/Polar-Technology-Kit-Zipper-Vest-with-6-x-15-Kool-Max-and-Cool58-Packs-p319.htm
Hope that helps.