Adding a grid to a Standard SAP screen

Hi, everyone.

     I wan to add a grid (that contains 4 fields) to a standard SAP screen (an OIF). And I want to save it with the host screen.   

     1.Should I use an EC?

     2.How can I save the grid with the Host xbo by using Save button on the host?

     3. Should I create a custom BO to save the grid?

Any help is appreciated.

Thanks.

Regards,

May T.