Copy Digital Certificate between workbooks

I have recently purchased a Code Signing Certificate and I am using it to
develop some excel applications.

One of the functions in an application that I have creates a new workbook
based on a template workbook. The Template workbook has the Code signing
certificate included.....when a new workbook is created using the template as
a basis and then saved on a users PC the certificate is not included....and
the standard Macro warning is presented.

Can you advise anyway to ensure that the code signing certificate is saved
with the new workbook on the users PC.....

Thanks
Scott