Stopping A Pipeline During Calculation?

Question

I just wrote up a blog post at http://geekswithblogs.net/JeffFerguson/archive/2010/10/24/solving-euler-project-problem-number-2-with-microsoft-axum.aspx that calculates an answer to a math problem using Axum. I note at the bottom of the blog post that I tried a more Axum-like pipeline approach to the problem, but that I couldn't get the approach to work. I was curious to see if anyone could come up with a more Axum-like pipeline-based approach to solving the problem. Any constructive criticism against the technique I wrote up in the post are welcome. Thank you.