Coarsely chop chocolate. Place in a small bowl and microwave on medium, stirring halfway through, until almost melted, 2 to 3 minutes. Remove and stir until smooth. In a large bowl, using an electric mixer,beat cream cheese with butter, lime juice and vanilla until smooth. Then beat in chocolate. Gradually beat in icing sugar until evenly mixed.
In a medium-size bowl, using an electric mixer, whip cream until soft peaks form when beaters are lifted. Stir one-third of whipped cream into cream cheese mixture until evenly mixed, then gently fold in remaining cream, just until no streaks remain. It's best to fill and frost cake right away. Sprinkle toasted coconut over cake. Don't refrigerate icing before using.