I should add to the notes, once the first two steps are done, preview the mission. An "Arsenal" option will appear on the object you placed. If your weapon supports bipods, the bipod does not appear. If there is a bipod in the crate then:

[_crate, (itemCargo _crate(+ _availableItems))] call BIS_fnc_addVirtualItemCargo

Will add the bipod from the crate but not from the list.

Neither "Item_bipod_01_F_blk" or "bipod_01_F_blk" work (Item or no Item, regardless of bipod type).