HydraExpress generates code to support the MIME bindings as defined in a WSDL document. Both referenced (the attachment is explicitly stated via a mime:content element in the WSDL) and unreferenced (the attachment is linked via the WS-I Attachments Profile 1.0 swaRef type as a field somewhere in the normal message) MIME attachments are supported. The MIME attachment bodies themselves are represented as instances of rwsf::MessageAttachment.