I know a couple of guys that make really decent products at very reasonable prices. I am sure they would both do a great job.
You can search for visiondann_com on ebay US. I think he has one listed for a VH4. However, he can make one for the Hagen if you email him.
As far as the other is concerned, I can take pictures of the cover for my Herbert and send them to you. Absolutely love his work and the covers are very durable. He's been making covers for me since 2008 and all still look like new. There's not a single stitch damaged from the road.