software

I am trying to create a model to solve a Kakuro puzzle, see www.kakuro.net
for information on the puzzle, but it is very simlar in nature to a Sudoku
puzzle with some minor difference. It is a puzzle where rows and columns
must add to a specified value, it out repeating the digit. For example, if
two cells must sum to 6, the choices are 1:5, 2:4 (3:3 is not an option
because the two cells would be equal). I have been able to set up a system
of equations that modle all of the cells, the the sums that rows or columns
must equal.

where I run in to issue is making sure that in a set of number on value
repeats, I have been able to use Delta() and =--(a5=a3) to determine if the
cells are equal or not, but when I put them into the solver constraints, my
results go from almost perfect to all 1's.

Any thoughts?