Preheat oven to 190 degrees C. Grease a Swiss roll tin and line with baking paper. Grease and flour the paper.
In a large bowl, beat eggs on high for five minutes. Gradually add white sugar and pumpkin. Add flour, cinnamon and bicarb soda. Spread batter evenly in pan. Sprinkle walnuts evenly on top.
Bake for 15 minutes or until cake springs back when lightly touched. Immediately turn out onto a linen towel dusted with icing sugar. Peel off paper and roll cake up in the towel, starting with the short end. Cool.
To Make Filling: Mix icing sugar, vanilla, butter or margarine, and cream cheese together till smooth.
Carefully unroll the cake. Spread filling over cake to within 3 cm of edges. Roll up again. Cover and chill until serving. Dust with additional icing sugar, if desired.