Has anyone installed this rack onto the factory roof rails of a jayco tent trailer? I cannot seem to get the metal feet for the cross-bars to line up with the slot in the roof t-rail. There is a moulded plastic spacer provided that, when inserted between the metal feet and the t-rail, aligns the mounting holes properly but then none of the supplied bolts are of the proper length to fasten the feet to the t-rail. Help??