This is the big selling point of JBI - as long as components are JBI compliant, they should run in any JBI compliant container. So the JBI compliant components from OpenESB should be able to be deployed into the FUSE ESB/ServiceMix. Please note that there are some SAP-specific dependencies for the OpenESB SAP BC and I'm not sure where to get those exactly.
1. Did you succeed with this approach?
2. Is it possible to integrate with SAP without XI/NetWeaver?
but I think with servicemix-bean you can call sap using jco ...
otherwise the next release of spagic.org will support sap natively.
spagic can call Talend jobs and now Talend can connect to sap via rfc, bapi,... (http://www.talend.com/document-download.php?doc=saptechwp&src=EmailingLS8_nov08)