Mud plugin with non static models

With regards to this [question](http://answers.gazebosim.org/question/13686/picking-up-a-soft-ball-using-dual-arm/ ) where I am tying to pick a soft ball, I tried to use the mud plugin for the entire ball. But mud plugin seems to work only for static objects. If static is false, then the object just falls through the ground plane, is there way of making the plugin work with non static models? `ball.sdf` .....0.130.13truetrue1000collisionball/mud_contact0.8100000.0finger::finger_link