if what diggsey suggested didn't work, then you could write your own draw_wireframe function. Putting a dot at each vertex wouldn't be too hard, but I'm not sure about lines connecting em. never worked much with vertexdata stuff.
it'd be something like this:
lock vertexdata for mesh _objectInQuestion_
null=make matrix4(1)
null=make matrix4(2)
null=make matrix4(3)
projection matrix4 1
view matrix4 2
world matrix4 3
for n=0 to get vertexdata vertex count()-1
null=make vector3(1)
set vector3 1,get vertexdata position x(n)+object_pos_x,get vertexdata position y(n)+object_pos_y,get vertexdata position z(n)+object_pos_z
project vector3 1,1,1,2,3
d3d_dot x vector3(1),y vector3(1)
next
I think that should work as-is, but i'm not quite sure. Never really used the project vector3 command before.