Help needed: Installing certificate for IPsec VPN

I have a Win 7 x65 Pro computer on my home network (set up as a work group, not a domain) to which I want to be able to connect using an IPsec VPN. Based on my review of the Event log, I believe that I do not have a needed certificate installed for this to work.

The log shows:

• Event ID 20192, A certificate could not be found. Connections that use the L2TP protocol over IPsec require the installation of a machine certificate, also known as a computer certificate. No L2TP calls will be accepted.
• Event ID 20171: Failed to apply IP Security on port VPN2-0 because of error: A certificate could not be found. Connections that use the L2TP protocol over IPSec require the installation of a machine certificate, also known as a computer certificate.. No calls will be accepted to this port.

I have spent some time looking around to try to figure out how to do this, but have come up empty. (Well, not empty. I have found pages that say to do something, but then offer no clear explanation on how 'something' is actually done. The one page which sounded most helpful, a Microsoft page, no longer exists.)

It seems to me that I should be able to install a self-signed certificate - is that an approach that would work? If so, how do I do that?

I would appreciate a pointer or two. Thanks!