Why is Norton Internet Security 2009 not using multiple cores?

Q1) Why is Norton Internet Security 2009 not using multiple cores?

 

I have 4 drives and 4 cores but I have to wait 4x as long for a full scan because Nortons scans one drive at a time on one processor core

 

Why cant you use the processing power at your fingertips instead of making me wait 4x as long on a quad core pc?

 

Sysinternals filemon.exe reports only one drive is being scanned by Nortons during a full scan.

 

I have XP Pro SP3/Q6600/4GB DDR2, WD Raptor X, Seagate 7200.11 x3