I need to dynamically build a GP in a script due to not knowing ahead of time the certs that need to be included. I do not see a programmatic way to do this but am going to try by editing the XML in a backup of a sample policy. How are the certificates encoded in these backups? Below is the one I added through the UI as a test.
<q1:Data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q1:Data>