not possible, period, sorry.
There's a workaround though:
On your monitor:
1 - detach AVS from the player
2 - make it a bit larger
than 512x384 / 640x480 /whatever resolution you're using
3 - Set your tv to that resolution (in windows)
4 - drag the window over to the tv, so that the edges of the AVS-window are no longer visible on the tv.
/edit: hi, micro.D