VBA Macro signing - Can only see self generated certs

[gherkin]

I am using the Macro editor in VBA opened from Word. When select a digital
certificate to sign with I can only see a self signed certificate even
thought the user's local certificate store has a CA issued code signing cert
as well. I notice that the self signed cert uses SHA1 and my other certs use
more advanced algorthims. Is there a limit on what algorithms I can use to
sign Word macros?

The EKU for the self signed cert and the CA signed ones are the same.


Thanks