It's strange isn't it, that although they appear in the parts book they don't have a part number associated with them.
You would have to have an original to use as a template. I don't know where you are, but down here they use metal strapping to tie pallets of bricks together. It's certainly the right thickness & is quite springy. It would be a fiddle to fabricate, however I'm sure if I was in that position I'd give it a go. Visit a building site & dig around a bit, take a pair of tin snips with you, good luck.
