How to Create a Custom Tab in MA ?

Hi ,

I have a requirement to add a new TAB and add around around 10 fields in the Custom TAB, I went to Page customization and added a TAB when I tried to add a Tab I see only existing Tabs,so  in set up I went system toolbar and selected contract tabset to add new custom tabs, but I don't have option to add new tabs.

How can I add new custom tabs in contract documents? Can any one please help me out on this.

Thanks in Advance.

Roopesh