GRIPKIT and UR5: ROS control

I have a problem with gripper ROS control.
The gripper is connected to Universal Robots arm (UR5) using the GRIPKIT by Weiss Robotics.

I use Universal_Robots_ROS_Driver and MoveIt Motion Planning Framework to move the arm, this driver supports tool control only for newer UR (e-series) arms, not for regular arms like UR5.

I can control the gripper with the UR teach panel, but I need to control it with ROS.
I have found several ROS packages for the Weiss WSG-50 gripper, but they only seem to work for a gripper connected directly to a computer (via TCP or CAN protocol).

Is there any way to control the gripper from ROS when it is connected to UR5 using GRIPKIT?

Thank you in advance,