Apply VAT after discount is applied?

[Steveio]

Hi,

Many products on my website are discounted. I would like to be able to apply VAT to the discounted price rather than the retail price.

Does anyone know if this is possible?

E.g.
Product retail price = £100
Discount = £10
Discounted price = £90
VAT @20% on discounted price = £18

I would like the Price on the product.tpl page to display as £108.00 but is currently display as £120.00 as the VAT is being added to the retail price.