Preps custom EPS marks issue

[destryer]

We use a custom EPS register mark in Preps. We need to change it and I can't get Preps to recognize the new EPS mark in the Setup> Add Custom Mark. The reason I don't want to drag it into the marks folder to replace the old one is it's used in SmartMarks on every template we have when I tried that before the Smart Marks ALL disappeared on the templates. I would like that not to happen again. I would like to replace the mark in the correct way in the application to replace the old. I've tried saving the mark as different versions of EPS in Illustrator on BOTH Mac and PC, with and without previews with no success but the mark is grayed out in Preps when trying to add it. Any suggestions?

[couriergraphics]

what workflow. We need an .eps & .pdf of the same mark in the marks folder.

[destryer]

We use Preps strictly as a template maker in Apogee. We build them in Preps and choose them in the Preps template manager in the workflow. I need to replace the marks that are already in the templates with an altered one.