sysguard in panel?

I know I once knew how to do this, but I've forgotten how, and can't find any documentation that tells me :-(

How do I add a ksysguard sensor display to the panel?

[The irony here is that I have two sensors already displayed in the panel, but I put them there so long ago that I don't recall how I did it, and can't figure out how to add a third sensor; I have it configured to show three displays, but the third just appears blank because I can't remember how to configure it to display a sensor.]

Doc