Arched beams

[GaryZed]

I'm currently using Revit Structure 2009 to draw some structural steelwork rooflights. I've managed to draw a series of curved beams to create an arched rooflight supported on vertical stub columns, but am unable to get Revit to create members spanning between these arched members. Does anyone have an idea how this could be achieved?

dwf attached!


Thanks in advance.