I finally had the guts to update Joomla AND Virtuemart.
Also changed the URL, so the site is up to date!

I thought is had something to do with de virtuemart settings instead of them altering a file.

Because of the pricing, i'm reluctant to update virtuemart. Maybe if they read this post, they can reply also.

Don't know. They solved it and mailed "we have cheked the problem and fixed it."
Cost me 2 support hours, but payed for by my customer. :)

The plugin is running. Couldn't get it running myself, but with two support hours this case is closed.

During shopping and at the registration, the following statements came up:

Debugging: shopper's country is not known; defaulting to vendor-based tax
Debugging: calculating tax based on vendor address

Aparently the country doesn't get through. I deleted cookies on every try.

The address of both VAT's are good. Country, phone, mail. All correct.

Yep, sure.

I just uploaded the ps_product.php to the administrator/components/com_virtuemart/classes folder overwriting the original. Same result.
I tested it with VAT DE118646776, Germany and VAT NL806078236B01, Dutch.

Simon,

I just tried that and it almost solves it.
Filling the VAT field with an german VAT, VAT is still calculated.

So almost, but not entirely

Seems not to be solvable, thus the module doesn't work.
Can i get a refund?

Yes, those are set.

I just did a fresh install of Joomla and Virtuemart. Set the tax code to EU and published the EU VAT ID user field. The store is Dutch.

Without filling the VAT field, VAT is calculated, as it should.
Filling the VAT field with an dutch VAT, VAT isn't calculated and that's not good.
Filling the VAT field with an german VAT, VAT is calculated and that's also not good.

I just purchased the module and the first check encountered a problem.
A business from the NL (same as the store) does not see VAT on the order, nor is it printed on the invoice.
When no VAT is filled, there also isn't VAT on the order/invoice.

I have one VAT field (NLD) filled.