F4 display on a table cell

I've a table cell which is bound to the 'Matnr" field. So in the display, I automatically get the F4 help, But in the display the F4 help button is not dispalying. If I press F4 on the cell, the search help opens up. But the users will not know that they have to press F4. Is there a way to indicate that F4 is availble on this field?

Thanks,

Ramesh