webMethods professional services has a package called multipart which contains the content handler that can decode multipart content. Contact webMethods support - they should be able to get it for you.
To send multipart using the http service, see this thread:
Send request to webMethods support for professional services. Here is the reply:
In later versions, we have some built-in services to hangle mime
data. Please refer to the ISBuiltInServicesGuide, chap 14 MIME Folder.
This describes all of the built in services available for handling mime
data. These services are located under the WmPublic package under the mime
This should provide all the functionality you need to handle multipart http
Is this right? Is anyone know how to handle multipart Http Post by using these MIME build-in services? Thanks.