Serializing XForm instances as SOAPAttach attachments

I want to present an instance of XForms in a web service as an SOAPAttach attachment . However, from the XForms 1.1 specification:

• 11.11.3 HTTP SOAP Binding

  The attribute method submission must be set to getor postto access the SOAP HTTP binding.

  I understand this means that the method multipart-post(necessary for SOAPAttach) cannot be used with HTTP SOAP binding?

• 11.9.6 Serialization as Partial / Associated

  • Additional Part Requirements

    • One piece for each node with a data type xsd:anyURI, populated by loading with:

  Since it explicitly states “populated by loading”, I suppose that means that XML instance data or other generated content can only appear in the first part of the body (unlike SOAPAttach requirements).

Do I understand correctly that each of these restrictions does not allow (initially) to present an instance of XForms as such an attachment; and therefore, do you need to create such serialization (for example, by processing an event xforms-submit-serialize)? Is there a standard way to do this or a library that could help?