Which App Server version are you using. If you're still working off the 4.2MR2 release, this class changed names recently and those docs refer to the current state of the code.
In MR2, this class was called "org.jboss.soa.esb.actions.soap.SOAPUIClient".
Also note that in MR2, that quickstart can only be run on 4.0.5GA of the App Server. We're working on fixing this right now. Sorry about the current state of things, but they will settle down very soon and hopefully you can try these quickstarts directly from SVN and have an easier time.
I have tested this sample on Jboss 4.0.5 GA AS and Jboss ESB 4.2 MR2.
I have just had a look at the 4.2MR2 codebase and the class can be found in the webservice_bpel quickstart. This has been moved into the core within the current codebase.
What you will need to do is copy that source file into your example and configure it as following.
<action name="soapui-client-action" class="org.jboss.soa.esb.actions.soap.SOAPUIClient"> <property name="wsdl" value="http://localhost:18080/acme/services/RetailerCallback?wsdl"/> <property name="operation" value="SendSalesOrderNotification"/> </action>