"foreign key check" for non-dictionary fields

Hi,

I have a table (ZT1) like MANDT, ID, KUNNR, F1,F2.... and KUNNR field is defined as foreign key . FK Cardinality is set to 1:CN and "check required" box is checked.

And i have a itab like ZT1.

When i place this field into the dialog screen (Open screen painter's "Dictinary/Program Fields Windows", type ZT1-KUNNR and place into the screen), I can see and control the "foreign key check" property in the Attributes windows.

But if i place the itab-kunnr (Open screen painter's "Dictinary/Program Fields Windows", type ITAB-KUNNR and place into the screen), the "foreign key check" property is disabled.

How can i enable foreign check for itab-kunnr?

Thank you.