Groupmanager help 'prefix'

Hello so as the title says , Now on my server you can see [FACTION]-[USERNAME]-[MSG] but i want [RANK]-[FACTION]-[USERNAME]-[MSG]

groupmanager.config : http://pastebin.com/mXTd8Dvu

essentials.config : http://pastebin.com/0vVrifWK

Than i have in the groupmanager folder backup config globalgroups and worlds and in the worlds folder i only have world with this file : http://pastebin.com/SRYpfCTH

Please edit them thanks !