Custom Railing Post

Create the profile (could be with any tool e.g. Morph, column, beam) and make sure the geometry is properly coordinated, for this profile Y axis is parallel to the reference line of the Railing

Select the profile and save this as a railing post by going to File < Libraries and objects < Save selection as < Railing post.

Select the new post in the railing tool as an inner post or a post and define the distance.