Hi,
Means you pass the data as sy-datum and it should be stored in field as MM/DD/YYYY
You can write custom conversion routine for the same.
Create a Function Group ZDATE and create 2 FMs
CONVERSION_EXIT_ZDATE_INPUT
CONVERSION_EXIT_ZDATE_OUTPUT
See standard conversion for more details
Create a domain of 10 character length and assign the ZDATE routine to it