Westok are a brand of Castellated beams. There are a range of Castellated beams already in the system as UK Castellated Universal Beam or Column. If these sizes are not what you require you will have to add the desired beam as a User Section. The holes along the web of the beam are not modelled when using these beams. If the hole positions are relevant or important to you, then you will have to add contour features to the beam web (make one then array it along the web).
