FOR CHARLOTTE: Place nectar in small saucepan. Sprinkle gelatin over. Let stand 10 minutes to soften gelatin. Stir over low heat until gelatin dissolves. Remove from heat. Puree 2 cups mangoes in processor. Place in medium bowl. Stir in nectar mixture, sugar and lemon juice. Place bowl over large bowl filled with ice water. Stir mango mixture occasionally until cold and beginning to mound, about 10 minutes. Fold in yogurt and half cup diced mangoes. Chill over ice water 5 minutes longer, stirring occasionally. Arrange enough ladyfingers over bottom of 20 cm-diameter springform pan with 2- 0.75-inch-high sides to cover completely, trimming as necessary. Halve remaining ladyfingers crosswise nad stand around sides of pan, edges touching and rounded sides out. Spoon mango mixture into pan. Cover with plastic; chill until set, at least 5 hours. FOR SAUCE: Puree strawberries and sugar in processor. Release pan sides from charlotte. Serve with strawberry sauce.