transit van ladder rack

[stevestar123]

hi,

Ive just bought a r reg transit van

It has two ladder holders on the roof rack like the ones you see on bt vans question is how do you secure the ladder to it just using the wrap round thingy at the back, I did tie a rop to the eye on the front bar throw it over the ladder and tie it to the thingy at back but ladder could still move back and forward a bit so am i missing something?

steve