Adding custom fields in add attachment button while creating contracts

Hi All,

I am new to SAP SRM , and have a following client requirement .

I need to add 4 custom fields in the pop-up screen which comes up after clicking on the Add attachment button in the 'Notes and Attachment' tab

at the time of creating a Contract . Please guide me the steps which I should follow to achieve this requirement .

Your help in this regard will be highly appreciated .

Thanks,

Sumit