Hi Marcel,
if you have customized version of ESXi installed, try this command in :
/opt/hp/hpacucli/bin/hpacucli
if you have not customized version installed,
you can find guide how to install hpacucli for example here:
http://www.v-front.de/2012/03/how-to-run-hp-online-acu-cli-for-linux.html