Why doesn't Spybot S&D show up in the Security Centre?

I have recently upgraded Spybot S&D from 1.6.0 to 1.6.2 & I noticed that for a while it showed up in the Security Centre (as 'turned on') along with Defender & Norton. 1.6.0 had never done this, but it still worked fine. I had to re-install Spybot 1.6.2 & it seems to be fine, but it has disappeared from the Security Centre again.

Has anyone got an explanation for this?