The following geodatabase features are not supported by ArcMap Services:
1. Relationships and relationship classes.
2. Routes (routes can be served but they lose their M awareness).
3. Domain descriptions.
4. Subtype descriptions.
In ArcIMS 9.2 GET_FEATURES requests made to Arcmap services with outputmode="newxml" returns domain and subtype descriptions as part of a query response. This does not work when ArcMap is the client of the service.
ArcMap Server not only relies on the COM-based ArcObjects that serves as a foundation for much of ArcGIS, but it also relies on ArcXML tags that correspond with the request/response within ArcObjects. Currently, there are no AXL tags that can handle these kinds of geodatabase features.
These are known limitations with no workaround using ArcMap Server.
These are not limitations when using ArcGIS Server. ArcGIS Server supports all features of the geodatabase.