ClamWin Free Antivirus does not scan files automatically (that is when you access or open a file), you need to scan a suspicious file manually before opening it. Hence ClamWin does not offer fully automatic virus protection and does not integrate with Windows XP SP2 Security Centre.

This will change once the on-access scanning component is released and ClamWin team is working on it.

Please note that if you use MS Outlook email client (not MS Outlook Express) then all emails are scanned automatically when you open them.