Setting Up Recoverable VAT Tax for use in Internet Expense

We are using 12.1.3 and are trying to determine how to set up recoverable VAT tax to be used in Internet Expense.  We have set up the tax code in EBusiness Tax with a rate of 20% and have added the code to the expense report template.  The intent is to have the employee enter the entire receipt amount, including the tax, and have Oracle split out 80% of the receipt to the expense account and 20% to the recoverable account.  If anyone could guide us on the proper setup of the tax, it would be greatly appreciated