Editing a ALV Grid

Hi all,

I have an ALV listing some records and I have a button in the application toolbar to enable the edit mode. When i click on the 'Edit' button, I should be able to edit the existing records only (which involves modifying the values and deleting a row) and I should not be allowed to insert new records ( the plus + button to be disabled? ). Is there a way to do that? Can you please help me out in this?

Thanks in advance.

Regards,

Venkat.