The HP DL180 G6 is indeed supported. The most common reason why hardware health is not listed as an option for monitoring on servers is that the required vendor supplied agent software is outdated, or not installed. You can find links to the latest versions of your vendors hardware agent software at the link below. For HP servers polled via WMI you will need to ensure that HP's Insight Management WBEM Providers for Windows Server 2003/2008 software is also installed, which it is normally with the latest version of the SIM agent.
SolarWinds Knowledge Base :: Latest required software used to monitor hardware health.
