the api docs don't mention you have to preface with emblem- and this way you can use any icon you want for your overlays. yes, this lets you shoot yourself in the foot, but if you pick a poor choice for the emblem icon that's your problem ;)

i looked in lxr to find overlay users, but couldn't find any ... but if i missed you and your emblems no longer show up, preface their names with emblem-