Hello Terry,
This is strange, did you create the data type enhancement in the SAP software component version? To properly create a data type enhancement, the following steps are needed:
1. A separate software component version
2. The SAP SCV should be referenced as a basis object to the SCV on step 1. There are two things to do this. One is to just add the SAP SCV under the Underlying Software Component Versions in ESR, the other one is to add it in SLD and then reimport in ESR e.g
In the picture below, ERECRUIT 6.04 is added as a basis object of the SCV
3. Once step 2 is done, save your changes and then create the data type enhancements on the separate SCV (not the SAP one).
4. Save and activate in ESR, generate the proxy objects.
5. If properly done, the enhancements should appear on the SAP data type, Message Type and Service Interface 
Hope this helps,
Mark