Exchange rate related

Hello All,

I have the following scnario, can it be possible in SAP,if possible and if you have any documents related to that please send me in pkp0512@gmail.com

Scnario:

When the Invoice raised by the Vendor the tax is calculated in a different exchange rate then during invoice verification. Requirement is the user want to use the same exchange rate as in the invoice during invoice verfication for the tax, so that the tax amount changed by the vendor will match with the invoice recorded.

Thanks

Prakash