In a post a few months back I outlined a quicker way of producing openings in beams using a customised framing family within Revit Structure 2011. see link https://revitstructureblog.wordpress.com/2010/08/05/openings-through-beams-in-revit-structure/
Link you YouTube Tutorial:
I was asked the same question again last week and thought I would revisit the problem using some of the new Revit Structure 2012 features. I created a new line based family and made a void sweep with three instance parameters for the Length, Width and fillet Radius and then set the steelwork to ‘cut with voids when loaded’. This worked a treat and is a much quicker, more controllable way of creating openings in steelwork.
If any of you would like a YouTube video tutorial on how to create this family then let me know!