If you pan inside cuebase, and the master in the cuebase mixer is not hard panning, then check your vst connections for proper patching. if it is ok at the cuebase master, then look at the patches in the sound card's control panel. Also you should look at the master in cuebase to see if there is other things not correct.
Also it would be helpful if you post the screenshots of them: (cuebase master, vst connections, and sound card patches in the m-audio control panel)
Thanks for replying. I've just posted some screenshots but here's the one re vst connections.