We use Flash on a VM running Windows 8.1. The VM is xendesktop and connecting via a Wyse HDX Zero Client.
We have the drivers recognised in Windows, tablet works great. We have Autodesk's Sketchbook working properly with proper pressure. I can open Flash with the pen, select File->New with the pen, but once the worksheet is active, the pen no longer works and only the mouse has mouse control. There is no error in the Event Log in windows.
I have found this issue with both CS6 and Flash CC. This makes the tablet unusable in Flash.