How do you use Droid Serif italic in a CCLabelTTF?


I would like to use the italicized Droid Serif font in my Android project for the text in my CCLabelTTF objects but I do not know how to reference it. What do I use here?

CCLabelTTF::labelWithString("Some Text to Display!", 
                            CCSizeMake(0, 0), 
                            "??????????",               /* What do I pass as this parameter for Droid Serif italic? */