Combine sugars, pineapple and juice, milk, corn syrup, salt, and butter in a 2 litre saucepan. Cook to 110ºC ., stirring occasionally. Remove from heat and add marshmallows and vanilla. Mix together to melt marshmallow, then beat until mixture becomes heavy and creamy. Add nuts. Spread in a buttered 20 cm square pan. Cut into squares when cool and firm. Makes about 49 pieces.