Tax / Vat Issue

[samoss]

Hello,

 

I am trying to build a function that when the user gets to the checkout and sees the final amount they have an option for a tick box to me ticked or not.

 

If the tickbox is ticked the VAT remains on the final order but if not then it doesn?t and is taken off.

 

The reason for this is that certain customers on my store receive VAT free because they are disabled as we are a charity and i need to install this on the website.

 

I have tried there methods in OSCommerce but because it needs the user to say whether they are disabled or not i can find a way.

 

Another way i thought was to have to buy buttons? Maybe a buy button with vat and a buy button without for disabled and non.

 

Any help would be amazing thank you