How do I create a Personal Digital Certificate that is marked 'exportable'?

I created a digital signature for signing my MSWord macros using SelfCert.exe. I am attempting to export the certificate to another PC. I follow the instructions found in the Certificate Manager Export Wizard and get this error when I click "Finish":

Error exporting the private key. The private key may not be exportable.

The Certificate Manager Export Wizard seems to be designed to create a file (for back-up or for export) based on a Personal Certificate with a Private Key; but it gets this error instead. Could find no help in MS Knowledge Base or White Paper - those sources just confirm my use of the Certificate Manager Export Wizard.

I have learned that SelfCert.exe calls MakeCert.exe. MakeCert supports an option of -pe which marks the private key as exportable. I can't figure out how to get SelfCert to call MakeCert with the -pe option (as a possible solution).

We have a small WIN98SE peer-to-peer network using MS Office 2000.