A couple of additional details:
I am using oracle's ojdbc14.jar jdbc drivers.
Views generated from the base table exhibit the same error. While you can edit the SQL, the alias is not part of the statement and appears to be added automatically.
You can select "Oracle ANSI Connector", but you need to change the Driver name in the properties panel in the Designer and also provide the correct JAR in the class path entry.
By using the "Oracle ANSI" entry, the command will be properly converted to be consumed by the Oracle. The auto generated queries are SQL-92 compatible, they are not Oracle specific.
In future releases, (6.1.0), Teiid would provide Oracle templates for the native Oracle drivers, but until then, if you want to add your own type you can follow the procedure as described in