I looked at the Pipe_alt.dat file before I put the post up and I guess my issue is I could not figure out what exactly I needed to modify. For this particular symbol THE PIPE_ALT.DAT

COL1(1) Drawing name used in the dialog for preview image.
COL2(40) Name to be displayed in dialog for graphic name.
COL3(75) Function used to draw the graphic in the drawing w/ arguments.

COL1 COL2 COL3
[ISOGEN Supplemental]

B2S.dwg Break In Location (2 level) graph2 "Isogen_BreakIn_2" 10

I found the B2S.dwg called out in COL1 located in C:CADWorx2018/Plant/Support and if I modify it then the thumbnail that you see in the preview when you add the item from the isogen supplemental will change. The COL2 is basically just the text string that shows up in when you add the item from the isogen supplemental. I thought that COL3 called out the drawing (Isogen_BreakIn_2) that the program used to draw the symbol on the iso, but when I modify that dwg it doesn't change anything. I modified it on C:CADWorx2018/Plant/Support. Is that file the one it uses to create the s-key for the iso? Or is it defined in the Symbol editor or in I-configure somewhere?