Combine wafer crumbs and 6 Tbsp. margarine. Press into 9x13 pan and freeze.
Spread sherbet over crust and freeze.
Spread ice cream over sherbet and freeze.
Combine lemon juice, 6 Tbsp. margarine and sugar. Cook until dissolved. Remove from heat and slowly add beaten eggs and a dash of lemon extract. Mix well.
Cook until thickens. Cool and spread on top of ice cream. Freeze.