I am seeing this in my log while I was debugging a different issue.
2012-10-03 09:20:24,533 DEBUG [org.springframework.integration.handler.ServiceAct ivatingHandler] - <Unable to attempt conversion of Message payload types. Component 'null' has no explicit ConversionService reference, and there is no 'integrationConversionService' bean within the context.>
Is this something I need to worry about? It seems to be working..