I am not sure which patch version of VSE 8.7i you are using but there was an issue addresses in Patch 3.
Patch 3 resolved issues:
Issue: The user dialog box for the scan task option, User may defer scheduled scans, did not appear when VirusScan 8.7i was managed by the McAfee Agent 4.5. (Reference: 534348)
Resolution: The VirusScan Statistics tray plug-in was updated to include this same functionality from the VirusScan Statistics legacy tray icon.
Opss.. I am using VSE 8.7 patch 4.