How do you insert Steel Structures!!

Hi! I'm new to Sworks & have been using Inventor previously! whenever I had to work in an assembly I just had to click on any steel profile & insert it. I could modify it also. I have tried the "Weldments" but am finding it is somewhat lacking in functionality. Beams & Channels don't cope properly. You can't position "Caps" inside tubes & now I see there is no way to offset an HSS Tube in the frames. My question is this. I have tried dragging & dropping a steel profile from the "Toolbox" but it is "Read Only"! Obviously that is no good. I have talked to another Solidworks drafter who has been using this software for years and he draws all his profiles from scratch & extrudes! Whats the sense of that! Surely there is a way to drag & drop a steel profile into either the assly or part & then modify anyway you want!

Any ideas Please!

Thanks

Paul Rymal

SolidworksParts And Features