Problem with Piano-Player from VSL (Vienna Symphonic Library) + Cubase Elements

I recently bought the Bösendorfer Imperial and I’m thrilled. It works perfectly with the stand-alone player.

However, when I load the player into the VSTi rack in Cubase Elements, an “Expression” control appears; fully turned up. I can’t find this function in the piano player.

It causes the same Piono player to suddenly sound much harder, louder and more aggressive than in the stand-alone player. It is impossible to play a quiet note.

If I turn down the “Expression” control on the VSTi instrument in Cubase, it works, but I feel less dynamic. In the piano player, “Dynamic” is at 100%.
It’s as if “Dynamic” and “Expression” multiply and produce a horrible sound, but that’s just a guess.

What have I overlooked here or what can I set here?

Thank you very much for any tips!

Win 11 + VSL Piano “Boesendorfer Imperial” (Standard) + Cubase Elements 12 Version 12.0.70 Build_464 + RME Babyface Pro + old keyboard

I also use the “SYNCHRON PRIME EDITION”, where everything works perfectly.
All controls on the rack correspond to a control on the instrument; but it’s another player.