Yeah I checked that, If I fly SU-33 and fly close to a Tanker (within 0.4 km), it will bring down the refuelling pipes automatically, but this happens only on refuelling way points defined on the mission editor. It is tough to connect the refuel bob of my plane to the dongles, cannot maintain the same speed and altitude for long (may be I have defective joystick or not concentrating enough). Also I noticed that the auto-pilot will not work if you are close to the tanker so you are left on your own to make contact with the tanker.
Also I have seen images on some sites, of Lomac Sim, where an A-10A plane was being refuelled in mid-air. So I think A-10A also allows refuelling in the game. I will update this post when I try it later during the weekend.