Under SCCM (and SMS), there are two different methods for the deployment of software "bits" to an end-user's system. These two different methods have clear distinctions in how they operate...
I've posted a page up here that details how I do ITMU deployments. Take a look. Most of the nitty-gritty is in the attached ZIP file. http://myitforum.com/cs2/blogs/jhuston/pages/how-i-do-patch-management...