OpenPGP signAndEncrypt - How is the signing key referenced?

We need to create a new PGP key to sign with for when we call the signAndEncrypt service in the OpenPGP package. We have to create a new signing key because our trading partner will no longer accept updated versions of our signing key were we extend the expiration date. Our concern is that we don’t know how WebMethods references the signing key when the signAndEncrypt service is called. We are not referencing it in our code and we don’t find any references to it in the and templates.cnf config files of the OpenPGP package. Does anyone know how or where the signing key is referenced when the signAndEncrypt service is called?