Aliased types are types defined via the typedef keyword. Each aliased type has a correspondent type in the xsd types section of the WSDL. Aliased types can be used inside an any type; thus an any type anyA containing an aliased type aliasA would be mapped into a xs:anytype anyA containing the aliasA type. This mapping works also from xml to corba. Notice that when the alised type is used explicitly (not inside an any type) for example as a parameter of a method, the base (not aliased) type is used. This is due to a loss of information during the idl to java compilation.
Known issue. There is a jdk know bug affecting aliased types. This bug rises only with sun orb and compromises the alias mapping from inside an any type in many situations. If the component must be used for this purpose the only workaround is to use a different orb.