Hi,
I started working on this some time ago but never finished. You basically have to redo it as a multivariate minima equation and use something like the simplex algorithm to get the right numbers.
If anyone happens to have an Ops Research background, perhaps you could provide me with some of the math. I pulled out some old textbooks to do it, but had trouble remembering all the details of formatting the equations properly to solve it (its been 20+ years since I took the course!).
Cheers,
Brad