Here is a quick way to get started when trying to send a message to the HttpListeningConnector within PeopleSoft:

Basic URL: http://myserver.com/PSIGW/HttpListeningConnector
Advanced URL: http://myserver.com/PSIGW/HttpListeningConnector?&Operation={MyServiceOperation.Version#}&From={MyExternalNodeName}

Next you need to generate a message to pass to this Target Connector. Use a simple SOAP envelope and wrap you message into it:

<?xml version="1.0"?>
<soapenv:Envelope xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/"
xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:wsa="http://schemas.xmlsoap.org/ws/2003/03/addressing/"
xmlns:xsd="http://www.w3.org/2001/XMLSchema/"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance/">
<soapenv:Header xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
<wsse:Security soap:mustUnderstand="1"
xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/"
xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd">
<wsse:UsernameToken>
<wsse:Username>{ExternalUserId}</wsse:Username>
<wsse:Password>{ExternalUserIdPassword}</wsse:Password>
</wsse:UsernameToken>
</wsse:Security>
</soapenv:Header>
<soapenv:Body xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
<{MESSAGE_NAME}>
<FieldTypes>
<{MESSAGE_RECORDNAME} class="R">
<{FIELD1} type="CHAR"/>
<{FIELD2} type="CHAR"/>
</{MESSAGE_RECORDNAME}>
<PSCAMA class="R">
<LANGUAGE_CD type="CHAR"/>
<AUDIT_ACTN type="CHAR"/>
<BASE_LANGUAGE_CD type="CHAR"/>
<MSG_SEQ_FLG type="CHAR"/>
<PROCESS_INSTANCE type="NUMBER"/>
<PUBLISH_RULE_ID type="CHAR"/>
<MSGNODENAME type="CHAR"/>
</PSCAMA>
</FieldTypes>
<MsgData>
<Transaction>
<{MESSAGE_RECORDNAME} class="R">
<{FIELD1}>SomeData1</{FIELD1}>
<{FIELD2}>SomeData2</{FIELD2}>
</{MESSAGE_RECORDNAME}>
<PSCAMA class="R">
<LANGUAGE_CD IsChanged="Y"/>
<AUDIT_ACTN>A</AUDIT_ACTN>
<BASE_LANGUAGE_CD IsChanged="Y"/>
<MSG_SEQ_FLG/>
<PROCESS_INSTANCE>0</PROCESS_INSTANCE>
<PUBLISH_RULE_ID/>
<MSGNODENAME/>
</PSCAMA>
</Transaction>
</MsgData>
</{MESSAGE_NAME}>
</soapenv:Body>
</soapenv:Envelope>