How to enter Pre-Paid Invoice without effecting Taxes.

Hi All,

For Standard incoices to the Supplier I require the taxes (which are setup in E-biz tax and assigend to that supplier).

But for  entering a Prepayment Invoice to the Same Supplier, I dont require taxes (like VAT,Excise,etc;) to a particular Supplier, which automatically calculating after validating the Invoice.

How can I comeover this Issue?

Thanks&Regards.