How to apply two textures to two sides of a cube

Yes, maybe this example might be helpful:

Graphics3D 800, 600, 0, 2
SetBuffer BackBuffer()

;create texture that contains numbers
SetFont LoadFont("Arial", 20, 1)
tex = CreateTexture(16, 16, 1+8, 10)
For i = 0 To 9
	Color 255, 0, 0
	Rect 0, 0, 16, 16
	Color 255, 255, 0
	Text 8, 8, i, 1, 1
	CopyRect 0, 0, 16, 16, 0, 0, BackBuffer(), TextureBuffer(tex, i)
Next

;create new mesh
mesh = CreateMesh()

;create surface 1
surf1 = CreateSurface(mesh)

;create 4 vertices
v0 = AddVertex(surf1,  0,  1, 0, 1.0, 0.0)
v1 = AddVertex(surf1,  0, -1, 0, 1.0, 1.0)
v2 = AddVertex(surf1, -1, -1, 0, 0.0, 1.0)
v3 = AddVertex(surf1, -1,  1, 0, 0.0, 0.0)

;create 2 triangles
AddTriangle surf1, v0, v1, v2
AddTriangle surf1, v2, v3, v0

;create surface 2
surf2 = CreateSurface(mesh)

;create 4 vertices
v0 = AddVertex(surf2,  1,  1, 0, 1.0, 0.0)
v1 = AddVertex(surf2,  1, -1, 0, 1.0, 1.0)
v2 = AddVertex(surf2,  0, -1, 0, 0.0, 1.0)
v3 = AddVertex(surf2,  0,  1, 0, 0.0, 0.0)

;create 2 triangles
AddTriangle surf2, v0, v1, v2
AddTriangle surf2, v2, v3, v0

;create brush, used for painting on the mesh
brush = CreateBrush()

;create camera
cam = CreateCamera()
MoveEntity cam, 0, 0, -5

;used for delaying counter
nxt = MilliSecs()

;main loop
Repeat

	;w = wireframe
	WireFrame KeyDown(17)
	;turn mesh
	;TurnEntity mesh, 1, 2, 3

	;counter that puts number's digits into 'c1' and 'c2'
	If MilliSecs() > nxt Then
		nxt = nxt + 250
		cc = cc + 1
		c1 = (cc / 10) Mod 10
		c2 = cc Mod 10	
	End If	
	
	;----update texture-----

	;select texture for brush
	BrushTexture brush, tex, c1
	;assign brush to surface 1
	PaintSurface surf1, brush
	;select texture for brush
	BrushTexture brush, tex, c2
	;assign brush to surface 2
	PaintSurface surf2, brush


	;render world
	RenderWorld	
	Flip

;esc = exit	
Until KeyHit(1)

End