Starts a new EDI composite data element on the current segment.
When called, a new composite data element is created in the current segment. You can then call WriteComponentString one or more times to write the individual components or subelements that make up this composite.
Call EndElement once you've written all components in this element.
This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)