‘Operations’ asset cannot be added as a stand alone entity directly in Centrasite. Operations are always part of the Service (Web Service/WSDL). Centrasite is not a web service design tool. You might need to use XML editors or notepad to add operation in your wsdl, if you are creating WSDL manually. If you are generating WSDL using SoftwareAG designer, you need to add operation to your descriptor and then get the updated WSDL.
In Centrasite you cannot create operation before a service. Operation must be referenced by a service. If you have previously created and imported a service in Centrasite. You can add new operation to the web service and re-import it again, then the new operation object will be added to Centrasite registry.
I am not sure what do you mean by “free text field”. You can always add new operations to existing service (if this is what you mean by extending a service).
Irrespective of whatever SOA governance tool you use, the concept of operation and service is same for web services.
#API-Management#CentraSite#webMethods