Ability to Reverse Settlement Discount That Was Entered Accidentally

Our customers would like the ability to Reverse Settlement Discount that was entered accidentally. At the moment it doesn't appear in the list in Sales Ledger or Purchase Ledger Adjust Transactions Reverse Transaction. The only way to do it is to enter a Payment or Receipt for the discount but as Sage will not let you post a Payment or Receipt with a 0 value you have to enter at least .01p and then reverse this, these extra two transactions would then need to be Allocated and Reconciled. This is very time consuming.