modded dff and custom col help needed

[virusct]

Ok, I have no problem getting my models into SA, but I tried to make a custom collison file and ever since the vehical will not show up. even when i try to spawn it into a garage it does not appear.

 

Basically what I am try'n to do is make it so that you can put stuff(motorcycles and cars) in the cargohold of the Cargobob helicopter. Both the model and col model have open ends (see below)so could that have anything to do with it? I know the model works with the original col but not the new one.