Hi there,
I hope you have received an answer by now. The best method is to use the Data Protector Virtual Environment integration agent (VE agent), you will need to down load the latest patches for your version and VEPA too. Please refer to the HP pdf on the process http://bizsupport2.austin.hp.com/bc/docs/support/SupportManual/c02589263/c02589263.pdf.
it works well I have a customer using version DP 6.21 with vSphere 4.1 over 2 clusters.