Use

http://wiki.service-now.com/index.php?title=Microsoft_SCCM_Integration_3.0

and pay particular attention to

http://wiki.service-now.com/index.php?title=Microsoft_SCCM_Integration_3.0#SQL_Script_Sample

We have completed integration and are testing with 2012. Be aware that while the computers are inserted into cmdb_ci_computer, the OS on that machine is updated into the computer record and does NOT get inserted into cmdb_ci_spkg, only programs found on the assets ADD REMOVE PROGRAM FILES table in SCCM will get imported.

This is what we will be struggling with as a result.
http://wiki.service-now.com/index.php?title=Software_License_Counts_and_Compliance_Checking#Unsupported_Features