If vehicle were created in editor with 0 ammo (so weapon text is in red) there is no way to rearm it from ammo containers.

However if the ammo was used up completely in game (weapon text is white) everything is fine.

PS. What I think happens is that there are no magazines loaded in weapons of a vehicle when weapon text is in red. There are empty mags when text is in white. So the rearming functions only refills existing mags, it won't add any new.

Also there is an inconsistency. In singleplayer vehicles are resupplied automatically. In multiplayer player has to select it from scroll menu.

Also locality of commands setAmmoCargo, getAmmoCargo and others should be clarified in Biki. Something weird tends to happpen to a scripted refilling ammo supply in multiplayer mission. {F25324}