yes its metal... but he said i have to give him a drawing, so he can make them bang on for the chassis... for someone else to fit.... i dcan do most things... or have a go at least.... but i dare not mess with that Jeff.
thanks tho 
You need to get under your van and measure the width of a single chassis member, then measure from one chassis to the other, and calculate the correct distance, or if you can get someone to help you take the measurements from the center of each chassis, so that when your guy makes the straps they will sit centrally directly above each chassis member.
When you measure the length of the chassis,( The size of your tank) make sure the fuel tank isn't in the way, If it is you may have to drop your fuel tank to fit it