If it's the bracket, then you can use lots of the PE set which includes tool brackets/clamps that you can fold. and for many of those baskets were fashioned in the fields, I don't recall that it's a standard on board accessory that was done in the factory. So I will presume that you can build it anyway you want. You can use plastic card to replicate bolted basket, or use copper wire to immitate welded basket such as the on on the Marder III.
As far as the rope goes, I am sure some point on the war, a couple Stug crews had used ropes to secure things on the vehicle.
Comes to the Stugs, the only limitation is your imagination. #:-) :-)