I am developing workbooks to be used in Excel 2007 and Excel 2003 that
use custom toolbars. I have a matrix and existing code in XL2003 that
uses the commandbar to build the toolbar. There is also code to create
the customUI.xml file for XL2007 in order to add a ribbon tab. The
files work as expected when opened in XL2003 and XL2007.

Until...

We have Microsoft Office Compatibility Pack installed that allows
XL2007 files to be opened in XL2003. When the file is opened in XL2003
and saved (the file type is not changed so it is still .xlsm) the
customUI.xml file is stripped out even though the conversion process
is used. Any ideas on how to retain the customUI.xml file?