Hello again,
You can always use SNMP but Wbem is the new standard for anything above windows 2003 and ESX 5.x.
Just add an domain account with local admin rights to your discovery settings. Don't use your own account because when you change your password the discovery will stop working and your account will lockout. Create an account with the above mentioned rights and use that for discovery.
Please read other replies i made in this forum. If you can't findthem let me know i will make a document and attach it to this post. Posts like these
http://h30499.www3.hp.com/t5/ITRC-HP-Systems-Insight-Manager/No-valid-working-Sign-in-credentials-Error/m-p/6295509#M57765
Kind regards,
Andrew