Restriction message

How can I show in UI a configurated restriction message ?

Hi to all ( Bonita 7.1.3 with Windows )

I see that if I use a BDM object in a task without a form, if I configure a Restriction in Contract for a field of the object, if the script of validation returns "false", when I execute the task, the message that I wrote at Restriction appears after click in submit button.

If now, I configure a form in the same task ( this form takes directly the attributes of the contract object ), when I execute the task, if the field doesn't pass the validation, the message of Restriction don't appears.