Travel and Expenses / Create Expense report / Mileage Details

Question

Hi all,
I have  a requirement to do some validations whenever the user enters the license plate number in
ESS Travel and Expenses / Create Expense report / Mileage Details  .The system must throw a message if the user enters a wrong license plate number.
How do i know whether this is ABAP WD iview or JWD iview.IS there any BADI or BAPI for the validations.
Where is the information about License plate getting saved.
I have created a custom infotype for my requirement. The license plate must be validated from the data present in this infotype.
Can someone post me some advice on this please.
Thanks,
Anil

Answer 1

Achieved by enhancing WDA Component FITE_VC_MILEAGE, view DETAILS_VIEW and added a post-method exit call to check if the licence plate entered by the users match the one saved on infotype 0017 or our custom infotype. So when the user clicks on either 'Accept' or 'Accept and New entry' buttons the license plate is check with the data stored on IT0017 or your custom infotype - If the license plate match then the user should be able to save the record but if this doesn't match then the system should throw an error message. created a custom message class in SE91.