more or less, what you have done is ok.
Workday connector works for custom attribute with the name ends with __c or with xpath too.
When you use __c you dont need the xpath, if the workday attribute is build properly(is a big if). Also, you need only of the Integration System ID in most cases.
Organizational Reference ID is another id for reading account from differnt OU in workday(if I remember correctly), so if your target system dont have this division of account, you dont need.
About the error, you are not reading this attribute correctly or are using it incorrectly.
Follow this step for exclude any possible causes:
- Check if you the permission for reading this attribute
- Check if this attribute is visible in response(usign soapui for example)
- Create an attribute without __c and assign it the effective xpath in the response (can you see this topic workday for an example)
later I have 2 questions:
- Are you using this attribute like identity attribute of app?
- Are you using this attribe in a ReferenceIDMap?
