On the Axiom -Press the Edit button. At the bottom of the screen is Hyper COntrol Mode. Press 0 on the keypad and this will toggle between Transport and Normal.
Counter intuitively, press 0 until it reads Normal.
Press soft key 1 on the Axiom to exit.
In Reason you need a lane in the sequencer for the master section. Select this, and you can control the sliders on the mixing desk with the sliders on your control surface.
For tighter integration look at the Nektar Panorama P4 or P6. They are about to release the P1 which has all the buttons and sliders without the keyboard.