DTExec ignoring the /Connection parameter
In SSIS 2008 design time settings get loaded at the last step. I think this is what failing you.
See this post for more information:
http://dougbert.com/blogs/dougbert/archive/2009/04/07/understand-how-ssis-package-configurations-are-applied.aspxArthur My Blog
March 14th, 2011 7:28pm