How can I add a third variable in the example exampleInt​GAMULTIOBJ​.zip, and constrain this third variable to be integer?

In the example exampleIntGAMULTIOBJ.zip i tried to add a variable, then constrain this variable too to be integer, by addding IntCon = [1, 2, 3] to each of the custom functions (which are int_crossoverarithmetic.m, int_mutation.m, and int_pop.m). Yet when I run it the third variable is not integer. What am I missing? R2013a Thanks