Change texture on model

BlitzMax Modules Forums/MiniB3D/Change texture on model

Tried this. Got a black screen when I added the PaintMesh function.
SuperStrict
Import sidesign.minib3d

Graphics3D 640,480,0

Local mesh:Tmesh = LoadMesh("model.b3d")

Local cam:Tcamera = CreateCamera()
PositionEntity cam, 0,10,-30

' Load the wanted textures
' This one is already used in the mesh, and we want to keep it:
Local keepimg:TTexture = LoadTexture("tex1.png") 
' This is the one we want to change the placeholder texture to:
Local replaceimg:TTexture = LoadTexture("tex3.png")

' Create new brush and replace texture
Local brush:TBrush = CreateBrush()
BrushTexture brush, keepimg, 0,0
BrushTexture brush, replaceimg, 0,1

' Paint the mesh
PaintMesh( mesh, brush )

While Not KeyHit( KEY_ESCAPE )
	UpdateWorld
	RenderWorld
	Flip
	Cls
Wend


Where did I do what wrong? :)

Edit: To clarify:
The model.b3d file contains 4 triangles. They are grouped two and two into two groups, and each group have one material. (Using the milkshape terms)

Edit 2:
Here's a ZIP with the textures, the bmax file and the model in both B3D and Milkshape format.
http://www.mediafire.com/?8ywy5dbz3z7