Gazebo_ros_control - lwa4p

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Hi

I have model of schunk_lwa4p and I want to simulate and control it in gazebo with ros controllers. Everything works fine but in URDF was specified hardware interface for actuators and for joints like this:

    <transmission name="${name}_1_trans">
      <type>transmission_interface/SimpleTransmission</type>
      <joint name="${name}_1_joint">
        <hardwareInterface>PositionJointInterface</hardwareInterface>
        <hardwareInterface>VelocityJointInterface</hardwareInterface>
      </joint>
      <actuator name="${name}_1_motor">
        <mechanicalReduction>1</mechanicalReduction>
        <hardwareInterface>PositionJointInterface</hardwareInterface>
        <hardwareInterface>VelocityJointInterface</hardwareInterface>
      </actuator>
    </transmission>

When I am starting robot simulation Position controller works fine but I got this warning

[ WARN] [1464031340.051142737, 0.613000000]: Joint arm_1_joint of transmission arm_1_trans specifies multiple hardware interfaces. Currently the default robot hardware simulation interface only supports one. Using the first entry!
[ WARN] [1464031340.052966217, 0.613000000]: Joint arm_2_joint of transmission arm_2_trans specifies multiple hardware interfaces. Currently the default robot hardware simulation interface only supports one. Using the first entry!
[ WARN] [1464031340.053790441, 0.613000000]: Joint arm_3_joint of transmission arm_3_trans specifies multiple hardware interfaces. Currently the default robot hardware simulation interface only supports one. Using the first entry!
[ WARN] [1464031340.054632026, 0.613000000]: Joint arm_4_joint of transmission arm_4_trans specifies multiple hardware interfaces. Currently the default robot hardware simulation interface only supports one. Using the first entry!
[ WARN] [1464031340.055426326, 0.613000000]: Joint arm_5_joint of transmission arm_5_trans specifies multiple hardware interfaces. Currently the default robot hardware simulation interface only supports one. Using the first entry!
[ WARN] [1464031340.056314374, 0.613000000]: Joint arm_6_joint of transmission arm_6_trans specifies multiple hardware interfaces. Currently the default robot hardware simulation interface only supports one. Using the first entry!

And then after this warning I have problem loading velocity interface

[ERROR] [1464031340.563829082, 0.947000000]: Exception thrown: Could not find resource 'arm_1_joint' in 'hardware_interface::VelocityJointInterface'.
[ERROR] [1464031340.563957255, 0.947000000]: Failed to initialize the controller
[ERROR] [1464031340.564171909, 0.948000000]: Initializing controller 'joint_group_velocity_controller' failed
[ERROR] [1464031340.564356884, 0.948000000]: Could not load controllers

Is it possible to load multiple hardware interfaces in gazebo_ros ??? or I could always load only one interface ?? I am using standart ros_control gazebo plugin.

  <gazebo>
    <plugin filename="libgazebo_ros_control.so" name="ros_control">
      <robotNamespace>arm</robotNamespace>
      <filterJointsParam>joint_names</filterJointsParam>
     <robotSimType>gazebo_ros_control/DefaultRobotHWSim</robotSimType>
    </plugin>
  </gazebo>

Thank you for your time and advices.