turnGravityOff tag doesn't work with groovy gazebo 1.5

edit

Hey,

I'm having a problem with switching off the gravity for my models. I'm using ros groovy with gazebo 1.5 (but I installed gazebo seperately because I wanted to edit the sources). When I first tried the roslaunch, my model from the urdf file wouldn't load, I got the error message:

XML Element[turnGravityOff], child of element[link] not defined in SDF. Ignoring.[link]

So I removed the code

  <gazebo reference="my_model">
    <turnGravityOff>true</turnGravityOff>
 </gazebo>

and the model would load correctly. But now its falling or doing other weird stuff like jumping etc... Does anyone know what the right tag for gravity off is for the urdf file without getting this error message?

thanks