I am playing the first mission of "Blunting the Spear," and I have two SPW 251/7 fitted with "assault bridge ramps." Can anyone tell me how to use these ramps to facilitate vehicles crossing one of the fords across the Rzadza River? I'm not seeing a special command for either the SPW 251/7s or the Pioneer units riding in them. And when I try a waypoint over one of the fords, I get a red marker making it clear that the unit cannot enter the ford.