cpucrust: First of all, Windows7 recognized my "Thrustmaster Firestorm Dual Analog 3" gamepad.
A way to tell is to "Run" from the start button "joy.cpl" which will bring up a dialog box.
However, I suspect the Thrustmaster was not "XInput" compatible, hence the problem with configuring it in the Trine setup.

The utility "x360ce" is an open source project. I would provide a http link but that might be against GOG forum policy - but using Google or other search will readily get you to the right site. When running it, I made sure the graphical view of all the XBox 360 controller switches/analog control were all assigned.

"x360ce" then generated a "x360ce.ini" file. The instructions then indicate to place the "x360ce.ini" file and the "xinpu1_3.dll" file in the game folder.

For Trine, the destination folder for me was "Program Files\GOG.com\Trine\"
In the controller configuration for Trine, I simply selected "Thrustmaster Gamepad" and left the
configuration on default (since default is already configured for XBox 360 controllers)

My first try on running "x360ce" I got the analog Y input reversed, so I had to run again and reconfigure the Analog Y direction on the controller view, followed with regenerating the new "x360ce.ini".

I apologize if this is more detail than wanted - but hopefully it may help you and others.
I found using "x360ce" to be relatively easy and I'm glad the project exists.

Incidentally, I have completed Trine. What an awesome game although I wish there was more levels to work through. I will be playing it again on a harder setting with local co-op instead of solo. Hopefully, Trine 2 will be available without DRM and make it to GOG

akelcik: .. You got me back with that mail You sent me that You want me back. :o) Great idea.