For a customer account to provide data for custom fields, a web services provider must first create the custom fields themselves by making a POST call to /dataExchangeSettings/customField and specifying the names of the fields to be created (http://portfoliomanager.energystar.gov/webservices/home/api/account/customField/post). This call can create custom fields at the account, property, or meter level.
In the test environment, after a custom field has been created, the data exchange provider can simulate the submission of custom field values by a customer. This is done by using the customer account's credentials to call /account/customFieldList/recipient/(dxAccountId) (http://portfoliomanager.energystar.gov/webservices/home/api/connection/accountCustomFieldValues/put). The ID provided in the field (dxAccountId) should be the account of the data exchange provider (i.e. yours). Different calls are required to update property level or meter level custom fields.
Note: The ability to submit data for a custom field on behalf of a customer is only available in the test environment as part of the Simulating Connection/Share Requests services.