Just found this posting on the SCE forums regarding integration of SCE and FCS:

 http://forums.microsoft.com/TechNet/ShowPost.aspx?PostID=1797488&SiteID=17 is the link,  The text is below from the forum posting:

 

Question 16:  Can I use Essentials 2007 and Forefront Client Security to manage the same computers?

 

Yes.  Please read through these configuration steps to understand how to use both products in the same environment.

 

Setup

Base requirements:

·         Essentials 2007 must be installed on x86 hardware.

·         Forefront Client Security must be installed in the 2 machine (or more) supported configuration from their guide, where the SCE server is the distribution server component.  No other FCS workload is supported on the Essentials server. 

·         All FCS managed machines must be SCE managed machines

 

Configuration notes:

·         If the FCS distribution server is installed on to Essentials 2007, it will alter the subscription and approval settings already configured.  The administrator will need to re-run the Update Management Wizard again to apply custom settings.  It is important that the “Definitions” classification and the “Forefront” product remain subscribed and declared in the auto-approval settings. 

·         If Essentials is installed on to the Distribution server running FCS, the same classification and product settings need to be applied.

·         The Essentials 2007 default client and server scan times fall 1-2 hours after the FCS scan, which may leave managed machines up to 22 hours stale.  We recommend using Group Policy to set the client scan time to 4:00 AM, and the Server Sync time to 1:00AM.

Operation

It is important to note that the purchased limits of the FCS solution must remain within the purchased limits of the Essentials solution.