When you start the scan from the console, it sends a command to the device to begin the scan but that scan is not 'managed' by the console - Once it starts it's running within the LANDesk Antivirus software itself and there is no option to cancel it from the Console.
You could get creative and stop the avp.exe process via script, but there would be multiple avp.exe processes and if it's allowed in your AV settings, you would be disabling AV protection. The LANDesk Antivirus service would restart it after about 10 minutes, but you would be without AV protection for that short time.
If the AVP process that runs the AV engine is protected by LANDESK Antivirus Self-defense, then Jay's option is viable.
From the windows command prompt type "Taskkill /?" for some ideas on how to kill the running process.
I would suggest /im avp*
Any luck on this? I want to make sure you have been taken care of.