Add a new custom column
You can achieve it by modifying the following files/methods:
- app/code/community/Fooman/PdfCustomiser/Helper/Pdf.php getDefaultColumnOrderAndWidth() and getPdfColumnHeaders()
- app/code/community/Fooman/PdfCustomiser/Model/System/Columns.php toOptionArray()
Lastly, please create an entry for the custom column under
app/design/frontend/base/default/template/fooman/pdfcustomiser/item.phtml
Don't forget to enable the column under System > Configuration > PDF Print-outs.