there are some redbooks published for this combination: IBM-i and SAP:
from 2001: - Implementing SAP R/3 on OS/400
http://www.redbooks.ibm.com/abstracts/sg244672.html?Open
from 2006: - Implementing SAP Applications on the IBM System i Platform with IBM i5/OS
http://www.redbooks.ibm.com/abstracts/sg247166.html?Open
from 2006: - SAP NetWeaver Java on IBM i5/OS
http://www.redbooks.ibm.com/abstracts/redp4200.html?Open
from 2011: - SAP Applications on IBM PowerVM
http://www.redbooks.ibm.com/abstracts/sg247564.html?Open
maybe you will find something interesting in those redbooks,
but some details may have been changed .....
for example:
new user concept
http://service.sap.com/sap/support/notes/1123501
SAPJVM instead of IBM-J9
APYSIDKRN
http://service.sap.com/sap/support/notes/1632755
HTH
Christoph