11-24-2011 06:35 AM
I don't think any version of SBS is officially supported any longer.
I haven't played with Essentials, so don't know specifics as far how it uses IIS, but in earlier versions of SBS, although technically you could get ACT! for web installed, it was a somewhat arduous and then prone to breakage when running Windows updates.
You might be better off putting your energies into installing on a straight version of Windows...