CHeck my videos on gelanz.com. I will post one shortly. THere are two ways to do this. Table-repeat-column model/rep and pick the dash field then select assembly.
I did in in WF4 at Tampa last year. There is a utility in WF4 to make an IGES parametric. Then you can delete it ot modify it. If that does not work download CoCreate PE free from PTC. It will modify any IGES or step since it is not history based editing.