SOAP is a data format. There are a myriad of ways to use it, including different protocols to transport it, and lots of implementations from all kinds of vendors and organizations. So I think you misunderstood something about that article.
SOAP is just the payload of some other application protocol, predominantly HTTP. The various standard bodies just tinker with SOAP headers. So I presume IBM SOAP would mean that they have put something in the header part of the SOAP Envelope.