In Symantec Endpoint Protection 11.x and 12.x Small Business Edition, TruScan (also known as Proactive Threat Protection, or PTP) is not compatible with any version of Windows Server operating system. Symantec recommends omitting TruScan/PTP when installing the product on these operating systems; if installed, the product status will be displayed as OFF.
TruScan/Proactive Threat Protection can be installed and run on all 32-bit non-server operating systems such as Windows 2000/XP/Vista/7 (x86) and 64-bit Windows XP/Vista/7
The "Scan for trojans and worms" and the "Scan for keyloggers" options are currently not supported on Windows server operating systems or 64-bit Windows XP Professional. The "Scan for keyloggers" option is also not supported on Windows 7.
Intrusion Prevention System (IPS) technology is fully compatible with Windows server operating systems, and should be used to protect all servers.
Support for PTP on 64 and server is In Development
https://www-secure.symantec.com/connect/idea/support-truscan-windows-server-oses
We may see this feature in futures releases