the message appears when the package "Rotations`OrientationalSampling`" is loaded and added to $Path. When Needs[..] is executed again, Mathematica looks to see if the package is already on $Path (and therefore loaded), and does not load again if it is there. So there is no way to force Needs[..] to regenerate the message a second time, without redefining the built-in Needs function, which might have unintended consequences, and is inadvisable. So there is no straight workaround for this.
However, as you discovered, executing or Orientations or OrientationsAndWeights will list the available orientational sampling schemes.