I got tired of cleaning and painting the stock stamped sheet metal oil filler. I must have done it 10 times over the years and I always thought I could come up with something cleaner. I found the filler neck and cap at Fisher Buggies here in Tampa. It's a typical VW aftermarket piece, but is made from aluminum and polished with a good fiting cap. And it had the breather hose fitting already installed.
I cut some 1/8" aluminum sheet to the correct size and epoxied the filler neck to it. I made another piece to go inside the gasket to hold it in place. The screws you see on the bottom postion it on top of the case so that the gasket lines up with sealing surface.
Than I had to figure out how to hold it to the case. I looked at diffrent ways to bolt it, but I came back to the clip/wire that is used on the stock unit. I needed to add spacers to allow the clip/wire to be tight enough to hold it down. So I added the 1/2" square aluminum tubing pieces with some shims to get it tight. After I installed it, I added some insurance with the plastic tie wraps.