HOWTO: Wake iMac automatically from sleep to perform scheduled virus scan??

Hello. Running Mac OS 10.6.2 on a new iMac, with NAV 11.1.1 (2) (for Mac). Can anyone help me to set the iMac to wake automatically to scan for viruses. As it is now, the scheduled scan at 2:00 AM does not run until I hit the space bar in the morning and wake the machine. I would prefer the vurus scan happen while I am not using the machine. And I would schedule scans more frequently. Thanks.