Thank you Catherine. So it appears as though there is no way to rename the attachment automatically, and all will have to be done by hand. The only option is naming the subject line automatically, then having each attachment manually renamed.
Does anyone know of a solution that would allow my people to simply drop the attachments in a folder and have them instantly/automatically renamed based on data in the xml file? This is a very cumbersome way around this, but it just isn't an option to have an entire group of people that will be getting these forms in the hundreds to be renaming them manually.