reference gazebo-plugin in urdf-description

Hi, I'm writing my first description of an robot using urdf. To control the joints i tried to write a plugin for gazebo following the tutorials (simulator_gazebo/Tutorials/GazeboPluginIntro and plugins/model_manipulation_plugin). The Problem is, it seems that gazebo doesn't load my plugin. I think it's because of my urdf-file. It looks like this: . . . . . . . . . .base_turntabley_first_motor_first_armfirst_arm_y_sec_motor When I start the Gazebo and spawn the model, everything is displayed, but the links should be in an other Position if the plugin is running. There also should be an output on my console, but there is nothing. Does someone have an idea? Thanks a lot! Georg