50 Hz pulley and belt for HP 9885M

[douze-bis]

I own an HP 9885M 8 inch floppy drive which I would like to configure for using with the european 50 Hz power supply system.

What is required is to replace the"60 Hz" drive motor pulley and belt with (slightly larger) "50 Hz" pulley and belt.

The part numbers I have are :
50358-SHU PULLEY, 60HZ
1535-3651 BELT, 60HZ

The part numbers I'm looking for are :
1535-3650 PULLEY, 50HZ
1535-3649 BELT, 50HZ
So far I have been unable to supply them.

Does anyone know how to supply those ?
Alternatively, I would gladly trade my 60 Hz pulley and belt for the 50 Hz version.

Cheers,
Frederic