Buying parts for your VW online can sometimes be frustrating when the original part numbers are required.
But hopefully, here comes the How-To find original VW Part Numbers for your Bus on this dodgy russian website:
https://ifinterface.com/prog/car/cp2/inprog.php

– Click on Welcome
– Click Free Services in the top menu
– Click CarProg2
– Choose you language, brand, model,…

Update:
You can also find the VAG ETKA here:
https://nemigaparts.com/cat_spares/etka/