Like EhevuTov said, you'll want to get some management agents that support your hardware.
While terribly convoluted (at least, for me - I'm not very clever), HP does provide management agents that use SNMP and WBEM to provide various systems information. The management agents are usually part of the Proliant Support Pack, but you can also get just the agents on their own.
A lot of times these agents tie in with a larger offering, like the System Management Homepage, which you mentioned (SMH) or HP Systems Insight Manager (SIM). If you already have the SMH installed, you probably already have the agents installed, it's simply a matter of configuring them to point to a different tool. There should be SNMP options on that management homepage (under the Setup drop down).
I've always found deciphering HP's various "bag-o-tricks" to be difficult, but a few of their tools can be extremely useful.