How can I perform a mail merge in SugarCRM 6.5 CE?

I am using SugarCRM Community Edition. I have installed the Sugar plugin for Word, and I can successfully login into MS Word and can Define Template. I can Upload the template into Sugar from Word by click on upload button in Word and can see this document(template) in Documents section of Sugar. But when I select some contacts to send them email through mail merge, Mail Merge option does not appear. I checked the box against Mail Merge in User Profile under Advanced tab. But in Admin >> System Settings , there is no any option of Mail Merge to check. How can I solve it?