“The webMethods Enterprise Service Bus (ESB, formerly Integration Server)…”
So the answer to original questions: there are no “plug-ins” because it is a full-blown product; “ESB concept” is possible
Is that the 3rd or 4th name change? IS was B2B Server. Was there another name before that?
A couple of bullet points from the fact sheet that gave me pause:
“* Fully supports web-service and SOA standards”
Hmm. There are “SOA standards?” Sort of, but not at the technical level where ESB lives.
“* Is interaction style independent (SOA and EDA)”
Neither of these are “interaction styles.” They are architectural styles. But I guess they had to get the hot buzzwords in there somehow. 
#API-Management#soa#webMethods