There's a whole heap of documentation on 7.5 here:
http://www.symantec.com/docs/DOC5131
including "Symantec™ IT Management Suite 7.5 powered by Altiris™ technology Planning for Implementation Guide":
http://www.symantec.com/docs/DOC5670
and "Symantec™ IT Management Suite 7.5 powered by Altiris™ technology Installation and Upgrade Guide"
http://www.symantec.com/docs/DOC5669
and "Symantec™ IT Management Suite powered by Altiris™ technology Migration Guide version 7.0 to 7.5"
http://www.symantec.com/docs/DOC5669