Adding VAT (Tax) to Shipping?

I currently have my store set up so that tax/vat is calculated on the order total less any discount amount but BEFORE shipping is added e.g.
Products £10
Less Discount 10% = £9.00
Tax @ 15% = £1.35 (£9.00 x 15%)
Sub Total £10.35
Shipping £1.00
TOTAL £11.35

I have now discovered that I should be charging vat on shipping also so need the tax to show as being charged on shipping amount too (I realise I will need to show postage rate as pre-vat amounts so the total still works outs the same e.g. shipping at checkout would show as 87p so that total including vat works out at £1.00) e.g.

Products £10
Less Discount 10% = £9.00
Shipping £0.87
Sub Total £9.87
Tax @ 15% = £1.48
TOTAL £11.35

We have many different postage methods and rates plus different charges for europe and worldwide as well as various local postage options and will show all postage amounts with and without vat/tax on our delivery prices page so customers know they are not being charged any extra. Leaving zencart as it is and manually adjusting each invoice so we allow for tax on each delivery is not practical due to the amount of different postage options and orders.

Any help appreciated.

ADDED - I saw an option a while ago on zencart which allowed you to set whether vat/tax was calculated on the product price, the discount price or the total price etc and thats how I got it to calculate on the price less the discount, but I cant find that thread on here or the option in admin - also had a look though my zen manual but cant see it there either.

Not really sure what the question is here, as although you have said what the setup is, you haven't actually asked a specific question....

If your shipping rates aren't currently adding tax to your order costs, you should look a tthe TAX CLASS option, under the specific shipping method. This should be set to a tax rate, however, if this option is missing, this may be why your system is currently not charging shipping.

Which shipping method are you using? Zones, Royal Mail etc.

Absolute

Sorry I did not make myself clear enough - at checkout there is a sub-total shown for all the products in the shopping cart, then vat was added onto that sub-total THEN shipping was added on - this meant that no vat was added onto shipping charges but as a UK vat registered company I had to charge vat on shipping too. I figured this out myself by changing the sort order in Order Total under Modules tab in Admin (incase anyone else has a similar problem) :)

For the record I was using MultiGeoZone MultiTable (mzmt)

I have just discovered this problem as well.
I think I've got it sorted by going to modules>shipping

then selecting the billing method and making it taxable