When adding a new expense line in Dynamics AX Enterprise Portal 2012 , you can choose some expense category which make the transaction date modifiable for the user. If the expense category is "per diem", the transaction date is not modifiable, but when I choose for example AirFare, the transaction date is modifiable.
What I want to know is what modification do I need to do to make the transaction date modifiable for the user when chosing "per diem" as the expense category.