Mounting under bed gas tank

[forestb]

I have a jazz plastic fuel cell mounted under my bed. It is currently being suspended by the 2 mettle straps that are made for the cell but those are meant to hold the take down to a flat surface. It also has 2 bars of l shaped angle iron running along the bottom of the tank from side to side and are suspended by 2 long bolts that go from the angle iron to the frame. The angle iron is more than adequate to do the job but also vary ugly. People have told me that I should hold it in using strapping material but I am not sure what they mean. What should I use that I can bolt to the bottom of the frame, loop around the bottom of the tank and then back up to the other side of the frame.

[forestb]

closer photo