it isn't my idea, I believe the builder is a member here but I haven't seen him post this here , instead of a strap over the top of the bottle, you weld a ring to the trailer, then bolt the ring on the bottom of the bottle into the ring on the trailer, slick! http://www.expeditionportal.com/forum/threads/87226-UAV-TD-(Urban-Assualt-Vehicle-tear-drop)-build/page50
post 494 of the thread.