I recently found this post about custom configuration for a Biztalk Solution by Micheal Stephenson. I found very usefull since I posted something about configuration files before. I just scratched the surface in possibilities concerning configuration for BizTalk. Micheal gives you great insight in how custom configuration can be done. In extension this post I found another possibility written by Paul Petrov using Enterprise Library for custom configuration. So there are a lot of possibilities doing configuration for BizTalk solutions and I am happy these two guys have contributed in explaining the options. It will take some time for me and maybe you too to explore all the options, but it will be fun.