Hey Mr_Smurf,
I have applied the latest version of this addon. Just to try and debug this sucker. I know it is difficult to account for all possible scenarios...I am having issues with the tax stuff; shipping tax and order tax.
shipping tax
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On orders with standard_shipping where the shipping drop-down displays, came up as blank form (no selections available.)
order tax
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when adjusting the quantity of a product, the order tax is not recalculated and updated. Actually it removes tax from the orders table field: order_tax, but leaves the original tax in the grand total.
My configuration
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My store is set to base tax off of the ship-to address, AND, I do NOT charge tax on shipping...only the cart items total after discounts are applied.
My one and only Tax Rate has a tax_rate_id='2', with tax_rate='.0725'. I believe this is how VM comes setup. I just changed the rate, country, and state.
All my products have a product_tax_id='2' set.
All of my shipping rates have a shipping_rate_vat_id='0' set. You have to change this manually in the db anyway, each shipping rate has no place to change the tax id in the VM form.
So, no shipping rates show up because it can't match the tax ids.
debugging attempts
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I created an additional tax rate: id: 0, state: FOO, country: FOO, and rate:0
now the shipping rates come up in the form. when selecting one and submit, it properly adjusts shipping charges, but shipping tax is added: shipping rate * my tax rate (.0725). I do not want shipping tax.