Using the partner's signing certificate for the first time

Since the partner might not always immediately begin signing with the newly-accepted signing certificate, the signatures of the messages received by the trading partner can be verified with either the original or newly-accepted partner signing certificates.  Once a message received from the trading partner has been signed with the newly-accepted signing certificate (referred to as “first-usage”), it is automatically installed as the active certificate in the panel and the original signing certificate is archived in the certs\archive directory.