Is it possible to implement this also for the pushback nodes ?
No, that's not how they work, and even if they did, it's not needed, since you can do that by simply positioning them.
You must understand those are not "just" splines which can be checked or compared to any standard spline-visualization software. Those are a SIMULATION of the *actual* pushback mechanics, which it's not a simple spline with control points, it's the result of taking into account the airplane wheelbase, the towbar length (if there is one), and the tow truck wheelbase too. That's why they cannot be treated as plain splines, but this way, you are 100% sure that what you'll see is what you'll get. Assuming, of course, you are going to perform the pushback with the same airplane + tow truck you used in Preview.
Or have you any Tip , how to set up this pushback?
It's not clear what you are trying to achieve, please clarify. And, Page 51 of the manual has an example at EDDP 402, which uses just ONE node, and doesn't seem very different what you are trying to do.
In fact, it looks *exactly* as you wanted it to be in your past post about EDDP 402, I chose that example for a reason...
If you are trying to do something different here, then please clarify.