Was your problem resolved?
Your namespace should have been more like:
http ://schemas.microsoft.com/[MyOracleDbAdapter://<DataSourceName>/<OracleSchema>/Tables/SAMPLE_XCHANGE]
If you generate a new schema check that against the one you have now. Once someone changes the Oracle database instance or user/schema it can have "negative" affects on your generated schemas. I've had to make sure that each environment (Dev, Test, Prod) has the same Oracle schema configuration so I don't need to re-generate my schemas for each. (Which would be bad) 🙂 Synonyms might solve this but I haven't tested.
BizTron