Index: src/main/java/org/activiti/designer/export/bpmn20/export/BPMN20ExportMarshaller.java
===================================================================
--- src/main/java/org/activiti/designer/export/bpmn20/export/BPMN20ExportMarshaller.java	(revision 2007)
+++ src/main/java/org/activiti/designer/export/bpmn20/export/BPMN20ExportMarshaller.java	(working copy)
@@ -244,7 +244,7 @@
       StartEvent startEvent = (StartEvent) object;
       // start StartEvent element
       xtw.writeStartElement("startEvent");
-      xtw.writeAttribute("id", startEvent.getId());
+      xtw.writeAttribute("id", subProcessId + startEvent.getId());
       xtw.writeAttribute("name", startEvent.getName());
 
       // end StartEvent element
@@ -254,7 +254,7 @@
       EndEvent endEvent = (EndEvent) object;
       // start EndEvent element
       xtw.writeStartElement("endEvent");
-      xtw.writeAttribute("id", endEvent.getId());
+      xtw.writeAttribute("id", subProcessId + endEvent.getId());
       xtw.writeAttribute("name", endEvent.getName());
 
       // end EndEvent element