Remote control of unmanaged devices with VNC

Is it possible to remote control unmanaged devices? We have Wyse terminals that we can enable VNC on, however when I try to remote control using the right click -> remote management route (the device has been scanned using SNMP/agentless discovery), I get an error that says 'Machine is not managed'.

Is it possible to get the Altiris console to ignore this limitation and just connect to the device using its VNC client?

Am running Altiris/Management Platform 7.1 SP2 MP1.1. pcAnywhere version is 12.6.7

Cheers