There is a hard coded reference in the HttpClientUtil.java class causing the client request to the Activiti service(s) to fail. I updated the code on my local build to match the domain I specified for SSO and it started working. Below is a copy of the exception and the line that is causing it to fail. BTW, so far it looks very promising... thanks for all the hard work.
culprit seems to be the below:
cookie.setDomain(".cn.ibm.com");
04/27/2013 07:11:39 AM HTTP JVM: 07:11:39,775 INF | 2013-04-27 07:11:39 127.0.0.1 - 127.0.0.1 80 GET /activiti-rest/service/process-instance/155 - 403 407 0 0 http://mambler-mac-win.rccl.com Apache-HttpClient/4.0.1 (java 1.5) - [org.restlet.Component.LogService]
04/27/2013 07:11:39 AM HTTP JVM: org.apache.commons.json.JSONException: Error occurred during input read.
04/27/2013 07:11:39 AM HTTP JVM: at org.apache.commons.json.internal.Parser.parse(Parser.java:116)
04/27/2013 07:11:39 AM HTTP JVM: at org.apache.commons.json.internal.Parser.parse(Parser.java:85)
04/27/2013 07:11:39 AM HTTP JVM: at org.apache.commons.json.JSONObject.(JSONObject.java:124)
04/27/2013 07:11:39 AM HTTP JVM: at com.ibm.xsp.xflow.activiti.ActivitiRestClient.getProcessInstance(ActivitiRestClient.java:62)
04/27/2013 07:11:39 AM HTTP JVM: at com.ibm.xsp.xflow.activiti.ActivitiRestClient.createProcess(ActivitiRestClient.java:56)
04/27/2013 07:11:39 AM HTTP JVM: at com.ibm.xsp.xflow.activiti.ActivitiRestAPI.createProcess(ActivitiRestAPI.java:37)
04/27/2013 07:11:39 AM HTTP JVM: at com.ibm.xsp.xflow.activiti.ActivitiWorkflowContext.initWorkflow(ActivitiWorkflowContext.java:42)
04/27/2013 07:11:39 AM HTTP JVM: at com.ibm.xsp.xflow.activiti.ActivitiWorkflowContext.executeAction(ActivitiWorkflowContext.java:93)
04/27/2013 07:11:39 AM HTTP JVM: at com.ibm.xsp.xflow.beans.WorkflowContextBean.executeAction(WorkflowContextBean.java:113)
04/27/2013 07:11:39 AM HTTP JVM: at com.ibm.xsp.xflow.component.UIWorkflowActions$WorkflowAction.invoke(UIWorkflowActions.java:318)