Keystation 49e, keys not working.

My brother gave me his old Keystation 49e which had a broken usb port, so i repaired the usb port by soldering a new one there and it worked fine. The device is recognized by windows (7) and it shows up in MIDI-OX. But when in MIDI-OX i only get signals from the wheels and volume, not the keys.

What could be the problem here?

Sincerely,
Farskies