A couple of things to ponder … first, there isn’t anything, at least in the US, called a “circling approach” … there is only the “circle to land” maneuver. Of course, there are several “instrument approaches” for which you can receive clearance to fly, and then, tagged on the end of the “cleared for VOR approach…” clearance (for example), you can get “…circle to land runway XX.” The actual circling “maneuver” is a visually referenced maneuver to get you from the end of the instrument approach to a different runway on which you are to land. If you do not have the airport in sight, including the runway to which you are to circle to land, when get to the point that you need to break off for the circle, you are obligated to execute a missed approach. If you have the appropriate visual references, you can break off from the instrument approach and maneuver (not below the circling minima, however) to align with the other runway. You must be able to keep the runway of intended landing in continuous sight throughout the maneuver (unless you’re flying a high wing airplane and the airplane geometry is the only reason for not being able to “continuously” see the landing runway), because if you do lose sight of that runway, for any reason besides the one I’ve mentioned here you are obligated to execute a missed approach. Now … in that case, you are expected to continue to turn in the direction of the runway to which you were circling to land until you can intercept the missed approach for the instrument approach you originally flew – and fly that missed approach procedure.
Next, at least in the US, I think you’ll find that the regulator doesn’t qualify any simulator for the “circle to land” maneuver unless all of what I’ve described above can be accomplished with the simulator set to maximum gross weight for landing of the simulated airplane, the weather set to the minimums for the approach, and the landing runway must be at least 90 degrees from the approach course for the instrument approach to be flown. That means the visual system capability in the simulator has to be good enough for the pilot to be able to perform the tasks described. There is no corner cutting in getting the simulator qualified … now, how the simulator is actually used may be an entirely different circumstance – but, if that is true, it’s not because of a limitation of the simulator. The regulator cannot afford someone learning a procedure in a simulator, that, if conducted in the real world, would lead to an accident or incident.