Problem with Email - Send with Document

I am having a problem with assigning an attachment name in my send with document process.

I can successfully send the email with the document but it doesn't have a filename. I have the xml data in an xml type variable and have verified that it is there using variable logger.
My problem is that I can't get the data out of of the xml variable to assign the name of the form being emailed. I need to use three different nodes for the file name. I have tried xpath and template but have had no luck.

Can anyone help?

Thanks,

John