Add additional columns in attachment list in Generic Object Services(GOS)

The attachment list in GOS mainly has 'Title', 'Creator Name' , 'Created on' columns. These 3 columns appear when i have attached any document using store business objects. Now i need to add 3 more columns to this attachment list. I know there is a way to it. I found certain links as well. but its not clearly mentioned how it is exactly done. I have attached a screen shot as well. Could anyone help me on this?