Bascially you have to setup a processing rule which will trigger a flow service and provides bizdoc in the pipeline.So grab the bizdoc/content using (bytestoString)which will give the edidata and next step will be parsing the edidata using envelopeProcess,convertToValues based on the schema (WmEDI services) which gives output of EDIValues (ST segment).
So map ST child segments to the target XML document structure what ever your requirement is(see the WmSamples packages of EDIToXML mappings as a referrence).And finally use the documentToXMLString or recordToDocument service gives output (xmldata)and route it to TN for partner delivery.
Please use the search functionality,lot of threads been already discussed on this procedure step by step.
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HTH,
#webMethods#B2B-Integration#Integration-Server-and-ESB