2.2.6.1.2 Dispatch Marshaling
If the ID specified in the method header is IID_IDispatch, the marshaled data MUST conform to [MS-OAUT] section 3.1.4.4.2, with the exception of what is defined in section 2.2.6.1.4 and section 2.2.6.1.5.
When using dispatch marshaling, [out] parameters MUST NOT be supported. [in] and [in, out] parameters MUST be supported. However, because COMQC is a one-way protocol, [in, out] parameters MUST NOT be filled with data returned from the server.