FP 90x: piano sounds not affected by pedal

[Auximon]

Hello, don't know if anyone out here could help with a quite odd issue: pedal (come along with the piano) is not working ON THE ACOUSTIC PIANO SOUNDS. You understand how frustrating that could be. Oddly enough, pedal works perfectly when playing all the other tones (electric pianos, synths,...).
The dealer couldn't help me (the problem seems a brand new one for them...) , so I returned and they are sending me another one... I am only curious to know if anyone here had the same problem and/or could come with a solution?
Thank you very much!

 

[Auximon]

I(PS I forgot: it's a Roland Fp90x piano)