Signing services determine the method and the CA involved in signing, and are required for every workgroup. Your organization works with DigiCert to define and set up the signing services that you require. DigiCert actually creates these services for you. Once created, you can assign these services to a workgroup using the web-based administration console.
You use the API to define signing services.
Work with DigiCert to define signing services. Use the web-based administration console to assign these services to your workgroups.