Fortunately, the Lisa Pathfinder project has already developed ion engines that would be helpful against that. While they generate very minuscule thrust, unsuitable for space travel purposes, they have enormous specific impulse, meaning they can go on for years stabilizing given object against solar wind, gravitational influences and the likes. Several such engines attached to the disk would easily keep it stabilized against solar wind, and another couple on the telescope part would keep it aligned.
Of course you'd need somewhat more powerful jets to turn it around aiming at a different part of the sky, and these would likely need periodic refuelling (note as the disk rotates towards another place in the sky, the telescope part needs to travel a couple thousand kilometers!) but we've got the stabilization covered.