water hammer effect on beam members

Command Reference > "Adding, modifying, and deleting beams" states that beam members cannot be subjected to steam/water hammer transient effects. Is this saying that you cannot apply water hammer force time history loads directly to a beam point? Or is it completely disallowing the use of beams in a force time history analysis? Thanks in advance for any clarification you can give me. I'm hoping it will be possible to construct pipe supports out of beam members for calculations that include water hammer loads.