Having issues mapping one mouse button to another with modifier

[supergimp]

Maybe this isn't possible, but I can't seem to get it to work. I have a Logitech MX Anywhere 2 mouse with two side buttons (button4, button5). I can see them in EventViewer just fine. My goal is to map either (or both) to left_shift (or right) + button3 (orbit in Fusion360).

EventViewer shows button presses just fine with no modification. I've tried:

          "type": "basic",
          "from":
          {
              "pointing_button": "button4"
          },
          "to":
          [
            {
              "key_code": "button3",
              "modifiers":
              [
                "left_shift" 
              ]
            }
          ]
        }

And EventViewer just shows button4

I can map button4 to any other key it seems but as soon as I add a modifier it just maps as itself.

Can I not map one mouse button to another with a modifier?

[honsa]

Did you found a solution?