Excel 2007 : How to save mail merge field matching data

Hello,

I am doing multiple mail merges from similar excel files to mailing labels in MS Word 2007. This happens over time, and not all at once. All the columns are the same on the excel files, but it is a complicated series of non-intuitive field matching parameters that make the labels come out right. Every time I need to do a new file, the field matching is blank, which is maddening. How can I store my field matching selections, so I can access them each time I reach the address block stage of setting up the new merge?

Thanks

PS: Also important, how can I view the existing filed matching parameters for an existing labels document that was created in a Word-Excel mail merge?