VAT Tax on Sales Return

Hi,

As per karnatka VAT Laws in case of sales return if the required documents are not given by customer then VAT credit can not be pass to customer on sales return.

Suppose if 12.5 % VAT is charge on Sales Invocie. When customer return the goods and he does not give proper documents then 0% vat will be charged.

When we create an sales order for sales return at that time we select the reference of original invoice. The Price and Tax details are directly picked up from original invoice.

Hence Tax details can not be modified at that time.

So is there any way to modify the tax and select 0% VAT while creating an order.