Transparency property apply to .stl mesh in Gazebo 7.0

Hello, I would like to add the transparency property to an object without success. The sdf file model is: truemodel://maze/meshes/maze_v2.stl0.0012 0.0012 0.00120.5model://maze/meshes/maze_v2.stl0.0012 0.0012 0.0012 The property transparency does not take effect. Any suggestions? I would like to reproduce the same behaviour as the /view/transparent menu from gazebo. Thanks in advance,