OVER high heat bring water and sugar to boil in a small saucepan, stirring constantly.
REDUCE heat; simmer 1 minute.
COMBINE chocolate pieces and sugar mixture in blender of food processor fitted with metal blade; whirl until cool to room temperature.
BEAT 3/4 cup of the cream until stiff peaks form.
USING rubber spatula, fold chocolate mixture into whipped cream, blending thoroughly.
COVER and freeze until firm, at least 6 hours.
USING blender or food processor combine strawberries with the remaining cream and creme de cacao; whirl until smooth.
COVER and chill until serving time.
DIVIDE equal amounts of the strawberry sauce into 6 dessert dishes and add scoops of the chocolate mixture.
TIP: Mousse can be prepared a day or two in advance.