In order to use CA signed SAML signature certificates you can add the certificates in the Service Provider Settings section.

Next, export your account’s Nirmata SAML Service Provider (SP) metadata and import that into your IdP. To export the SP Metadata go to Settings - SAML 2.0 and click on the View SP Metadata option. You can then copy the metadata or download it to a file.

To complete the setup, you can now import the SAML SP Metadata into your IdP.