[Correction:  The Vista SP1 package will be availabe via the Microsoft Update Catalog - I'll provide a link to the KB article detailing how to import Vista SP1 into Essentials once the article is live!] 

Windows Vista SP1 will be released as an update on Microsoft Update (MU) Catalog. The patch is very large and there is a bug in Windows Server 2003 in the WinVerifyTrust API that will cause signing validation to fail.

What this means is that once you approve this update on a System Center Essentials 2007 server on a Windows Server 2003 server, every time the server sync’s from MU it will redownload the package, fail the cert validation, and so the download will fail. The problem will continue until you install the WinVerifyTrust patch on the System Center Essentials server. This patch is a hotfix (not a public GDR), so is not intended to be widely distributed. We recommend it only be installed on the System Center Essentials server itself.

You can obtain this hotfix here:

Windows Server Update Services cannot download large Windows update files in Windows Server 2003
http://support.microsoft.com/kb/888303/en-us

Hi Folks,

IE 7 will be distributed via WSUS in February as an update rollup package.  If you chose the default settings when configuring Updating Management in Essentials 2007, this package will not be automatically downloaded and distributed to computers in your company.  If you wish to have it distributed automatically, check out this KB article.  Its instructions are for WSUS, but will also work for Essentials by changing its Update Management settings to include update rollup packages.

Windows Internet Explorer 7 to be distributed via WSUS February 12, 2008; May require administrator action to manage the rollout
http://support.microsoft.com/kb/946202/en-us