Rear (parking) brake plate sub-assembly wanted

Hi everyone, I'm looking for sub-assembly plate for the left rear wheel on european model of Prius Gen 2 2007. It's the metal round plate that covers the disk brake from the inside preventing the dust coming into the brake and also functions as a base for the drum parking brake installed within the disk heart. It's also called "anker" plate. Official Toyota part number is 46504-32020 and I'm attaching the service cut-out illustration.

I recently head to replace the wheel bearing only to find out that this plate is totally rotten... I cannot find replacement part anywhere here where I live, and all the used Priuses I found on the junk yards had that part also pretty rotten. I cannot find it anywhere on the ebay or amazon, and the original part cost a fortune. Like more than 10 times this things cost for any other car... Can anybody help me find this part for reasonable price?

Thank you very much