Has anyone purchased a First Gear Torrent Waterproof Duffle Bag and used it on their F6B? I'm looking for a waterproof bag to strap to my MP3 rack. As I plan to do a fair bit of travel this summer, I'm thinking the 70 liter duffle would be helpful - but I'm not sure if it would fit/tie down well. They also offer a 40 liter duffle - but I could use more space. Here's where I saw it online: http://www.motorcycle-superstore.com...oof-duffle-bag