BPEL hanging when using HeaderHandlers for stateful webservice

Question

We are having problems calling a partnerlink using the responseHeaderHandlers and requestHeaderHandlers properties.
The problem seems to be that the response from the webservice of the partnerlink is never received by BPEL, resulting in a timeout.
From the BPEL logs, I can see that the outbound header handler class has modified the request:
06/09/06 10:00:03 Started alive handler for statefull support -> out
06/09/06 10:00:03 [Request] to RetrieveServiceContent operation
06/09/06 10:00:03 Modified props
06/09/06 10:00:03 Outgoing call props: {is-initial-call=true, input-header-variables={}, parentId=1902, completionPersistPolicy=null, process-id=bpel://localhost/default/VMTest~1.0/, rootId=1902, conversationId=bpel://localhost/default/VMTest~1.0/1902-BpInv0-BpSeq1.6-2, location=http://wxp03666/sdk/vimService, priority=3, httpRequestHeaders={Connection=Keep-Alive}, work-item-key=1902-BpInv0-BpSeq1.6-2}
And in obtunnel, I can see the reqest being sent to the remote web service:
POST /sdk/vimService HTTP/1.0
Via: 1.0 LON-MEM-APP-11
Content-Length: 342
Content-Type: text/xml; charset=utf-8
User-Agent: orabpel
Host: lon-mem-tsg-06.lon.domroot.com:80
Accept: application/soap+xml, application/dime, multipart/related, text/*
Cache-Control: no-cache
Pragma: no-cache
SOAPAction: ""
Connection: Keep-Alive
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<soapenv:Body>
<RetrieveServiceContent xmlns="urn:vim2">
<_this type="ServiceInstance">ServiceInstance</_this>
</RetrieveServiceContent>
</soapenv:Body></soapenv:Envelope>
The remote webservice receives this request, and in obtunnel I can see it's response:
HTTP/1.1 200 OK
Date: Wed, 6 Sep 2006 09:00:03 GMT
Set-Cookie: vmware_soap_session="19D82F52-CC94-4E52-9A2A-54AB10A31E3C"; Path=/;
Cache-Control: no-cache
Content-Type: text/xml; charset=utf-8
Content-Length: 2106
<?xml version="1.0" encoding="UTF-8"?>
<soapenv:Envelope xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/" xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<soapenv:Body>
<RetrieveServiceContentResponse xmlns="urn:vim2">
<returnval>
<rootFolder type="Folder">group-d1</rootFolder>
<propertyCollector type="PropertyCollector">propertyCollector</propertyCollector>
<about>
<name>VMware VirtualCenter</name>
<fullName>VMware VirtualCenter 2.0.0 build-27704</fullName>
<vendor>VMware, Inc.</vendor>
<version>2.0.0</version>
<build>27704</build>
<localeVersion>INTL</localeVersion>
<localeBuild>000</localeBuild>
<osType>win32-x86</osType>
<productLineId>vpx</productLineId>
<apiType>VirtualCenter</apiType>
<apiVersion>2.0.0</apiVersion>
</about>
<setting type="OptionManager">VpxSettings</setting>
<userDirectory type="UserDirectory">UserDirectory</userDirectory>
<sessionManager type="SessionManager">SessionManager</sessionManager>
<authorizationManager type="AuthorizationManager">AuthorizationManager</authorizationManager>
<perfManager type="PerformanceManager">PerfMgr</perfManager>
<scheduledTaskManager type="ScheduledTaskManager">ScheduledTaskManager</scheduledTaskManager>
<alarmManager type="AlarmManager">AlarmManager</alarmManager>
<eventManager type="EventManager">EventManager</eventManager>
<taskManager type="TaskManager">TaskManager</taskManager>
<customizationSpecManager type="CustomizationSpecManager">CustomizationSpecManager</customizationSpecManager>
<customFieldsManager type="CustomFieldsManager">CustomFieldsManager</customFieldsManager>
<diagnosticManager type="DiagnosticManager">DiagMgr</diagnosticManager>
<licenseManager type="LicenseManager">LicenseManager</licenseManager>
<searchIndex type="SearchIndex">SearchIndex</searchIndex>
</returnval>
</RetrieveServiceContentResponse>
</soapenv:Body>
</soapenv:Envelope>
However, the BPEL logs don't show any trace of BPEL receiving the response. The only thing that happens is the timeout.
If I remove the HeaderHandler properties from the partnerlink, BPEL receives the response from the remote web service ok, and continues with further invocations of operations. However, we do need to maintain state accross invocations, so need to use header handlers.
I have managed to get this code working on bpel 10.1.2.0.2 dev install, and thought the problem was due to setting the pl property httpKeepAlive to true, which appeared to modify the request to use http 1.1, from http 1.0. I set httpKeepAlive to false and it started working.
Now that I've deployed to BPEL on 10g apps server (10.1.2.0.2) the problem has come back again.
I have tried to ensure that everything is identical (classes being used etc), but cannot resolve the problem.
Can anyone help?
Toby

Answer 1

We have resolved this problem now, and a couple of things were creating the problem.
1st, httpKeepAlive property of true on the partnerlink resulted in a request being sent to the webservice, but no response being received. We set it to false as the outbound header class modifies the header to include a http keepalive of true.
2nd, requests were going through a proxy server, and this was affecting things. Once we disabled the proxy server for the apps server where the requests were originating, the process worked.
Thank.
Toby