Disabling 'Change' and 'Delete' button in Attachment List in ME52N

Hi Friends,

The reuqirement is this:

A user attaches doucments ( using the Generic Object Services to attach document ) while creating/changing Purchase Requisition (ME51N / ME52N).

Now when any user goes to see the docuemnts attached to the PR, he selects the 'Attachement List' from the context menu, he should only be able to read it and should not be allowed to change or delete the document. For this we need to disable the 'change' and 'delete' buttons from the toolbar.

Awaiting your response.......