Malware protection no longer visible in security center

> I've just installed Windows Vista Ultimate. On top of it I installed
> McAfee
> Virusscan 8.5i. After installation the Security Center kept warning about
> the
> AV and asked if I would like to activate it and so on. Until I explicitly
> said yes to the question regarding activation there was a little re ring
> with
> a slash on the Viruscan shield in systray. I continued and managed to get
> the
> VPN working and joined the company domain. After joining the domain
>
> a, I can't anymore manage all aspects of security through the security
> center. The Help function in Vista informs me that I should 1, Click to
> open
> Security Center. 2, Click Malware protection .. well that is not there
> anymore!!
>
> b, I've disabled every single security feature in the computer. Before
> joining the domain I got warnings about that with Window poping up shields
> in
> the systray warning me about various security measures not working
>
> c, I'm unable to activate the on-access scan feature of Virusscan 8.5i.
> The
> little red ring with a slash is showing on the Virusscan shield in
> systray.
>
> What is this? As far as I know, there is no GPO affecting my computer.
> Where did Malware Protection go? Why am I not able to run on-access scan?
>
> best regards
> Johan
>