Myself and two of my friends are experiencing the same problem. RWS does not pick up the targets untill they are closer than 15NM which is too late in BVR engagement. TWS does pick up the targets at approx 40NM.
I think with data link, 40NM is good enough. you already know where the targets are through data link. Radar is required only for the missile launch.
But still I think Radar is not working as it Should.