In saucepan, sprinkle gelatin over 6 tablespoons water; let stand 1 minute. Add sugar; cook over medium-low heat, stirring constantly until gelatin dissolves. In blender container, process watermelon, strawberries and soymilk on high speed until puréed. Add gelatin mixture; process on medium speed to combine. Strain mixture into bowl, cover and refrigerate until thoroughly chilled. Process mixture in ice cream freezer according to manufacturer’s directions.