Maybe you could do something like this:



You could create a panel with the needed resulotion (640x480) and put it on front of the 3d entity

Code:
BMAP* window_pan = "windows_pan.tga";

PANEL* windows_pan =
{
	bmap = window_pan;
	layer = 15;	
	pos_x = 0;
	pos_y = 0;
	flags = D3D | OVERLAY | VISIBLE;
}

ENTITY* 3d_object =
{ 
	type = "sf_alien.mdl"; 
	layer = 10; 
	view = camera; 
	x = 350; 
	y = 134; 
	z = 100; 
	flags = BRIGHT | TRANSLUCENT;
	flags2 = VISIBLE;
}