Hello GuidoDamm and thanks for the quick reply again,
I have now updated my Tecnomatix to 12.1.
I tried the first option and defined my device as a gripper. I had to do simple logic block for the grip and release operation controls to use them at the correct time. And now it is working!
You said I could use material-flow viewer but I am not quite sure how should I do that because there wasn't any operations on my device before I added grip and release operations?
And I am using a robot to give the appearance to the device, so I also tried to use attach on OLPs but it will generate an unexpected appearance at the start of robot operation where I used the Attach command.