Drain pineapple, reserving 1/2 cup syrup.
Drain sweetened berries (be careful not to mash them), and to the juice add enough boiling water to make 1 cup; pour over gelatin and stir to dissolve.
Add pineapple syrup, lemon juice, and salt to gelatin mixture.
Chill until partially set.
Gently stir in berries and pineapple tidbits.
Pour into individual molds.
Chill till set.
Frame each pineapple slice with leaf lettuce; unmold salad atop.
Garnish with whole berries.
Pass bowl of mayonnaise or salad dressing.