Hi,

Thanks for the post!

For managing ESXi via OpenManage Essentials you need to configure\install OMSA(.vib) package on it. Once you are done installing OMSA package on it, you need to use WSMAN protocol to perform discovery&inventory for an ESXi target.

For Discovery&inventory, you can refer to below whitepaper:

http://en.community.dell.com/techcenter/extras/m/white_papers/20061803.aspx

For Installing OMSA(.vib), you can refer to below post:

http://en.community.dell.com/techcenter/systems-management/f/4494/t/19424735.aspx

What's the server model on which ESXi is installed?

Keep us posted.

Thanks

Ranveer