Press the button to the left of the Mount box (or press D). This will bring up the Mount decoration window.
(Note: Button will not work if Mount Box is empty - you must enter the number of mounts first)
Enter the number in the column beside type of mount enhancement required.
The Clear button clears all entries (i.e. No decoration) while the Ok button accepts the entries and applies the appropriate prices.
Mount Decorations and prices can be defined in the Options|Prices window.