In Plant3d space there is no feature available for modelling beams and columns.
Presently we are modelling the beams and columns using normal autocad command Extrude.
If modifications required we have to delete and do it again.
We learned how to extract support drawings from Plant3d, however, we find diffultly to annote the beam reference for the support as there is no intelligent for columns and beams, hence we have keep the reference manually.
I feel, it will not be a big task for Autodesk to provide the shape intelligent for beams, columns in Plant3d space in the upcoming Plant 2014 release, as this is an imperative feature required.