Milan,
Think there might be something getting lost in translation. All Flight Test Engineers fly on the air vehicle to some extent (assuming it has crew accommodations, which might not be true for all aircraft now, I admit) but if you are not particularly interested in flying then becoming an engineer in the Flight Test organization would definitely be the route to follow. How much you could fly depends on the discipline you are following, engineers fly most in support of Avionics systems either as an active participant in the testing and/or as a flying reference - is the system operating as expected? A very large part of current Air Transport testing is in support of Flight Management Systems (FMS), where it's often not clear cut that the system is either providing the correct guidance or displays. An Avionics Engineer from either the manufacturer or equipment supplier (such as Rockwell Collins, Honeywell or Garmin) will be either in the cabin watching a repeater screen or, more often, in the jump seat in the cockpit to better see what is going on.
Paradoxically, in my experience, Flight Sciences (Aerodynamics) do the least flying but the most flight following via telemetry owing to the inherent risk of envelope expansion.