Refferances

Hi All,  I had a problem last week where if I drew in context in an assemble.  After saving the part in an external file.  I could not edit the part as it automatically became a derived part.  I was told to cut the references to the assemble and sure enough all was well.  However, now if I draw a sketch in an assemble and try to use Weldments, the weldment profile has no references on it to be able to locate the profile.  I can make a new drawing and use the same weldment profile and it has the reference points on it.  Also when drawing in context I cant edit the sketch.  If I try to change a dimension iit re locates the sketch to a different location in the assemble.  I cant use any of the relations to locate the sketch!!!  I have attached the files.  If anybody can shed some light on this please.

SolidworksDrawings And Detailing