Sales order Item - Additional data B

Dear friends,

I added zfields in sales order item level Additonal Data B. Now want validate one field as obligatory and error should be shown in incompletion log.

Here the second requirement is to add a button with Fcode on Additional data B screen, and want to add some functionality on click of a button. Can i add Fcode functionality on Additional data B screen.

Regards,

Praveen Lobo