SwA is a W3C Note. It was submitted as a proposal, but it was not adopted by the W3C. Instead, MTOM is the W3C Recommendation for handling binary data in SOAP messages. With the release of SOAP 1.2 additionally the note SOAP 1.2 Attachment Feature1 was published.
SOAP 1.2 Attachment Feature by the W3C's of 8 June 2004 http://www.w3.org/TR/soap12-af/ ↩