another way to make canvas rolls is to use the puree tube method mentioned above but glue on tissue paper with PVA, once dried, fold and roll then paint them for your desired look.
buckles for strapings can be made from wire, just loop it around a scale sized square bit of wood or whatever comes to hand, as long as it is square, (rectangular will be fine too), slip the wood or whatever is used out and then cut down one side to free the buckles glue to straps and fit around the rolls/stowage, hey presto
