Vertex alpha not working any more?

Tried to follow this tutorial, but it´s not working.
http://guildofwriters.com/wiki/Decal_Blending
Is the vertex alpha blending not supported any more (pyprp 1.5.0, Blender 2.48a)?
http://guildofwriters.com/wiki/Decal_Blending
Is the vertex alpha blending not supported any more (pyprp 1.5.0, Blender 2.48a)?