MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
Have you considered changing the cap to a screw cap instead of the press kind? You won't have to superglue the end then.
I've recently started remixing designs, but I haven't reached the skill level to design screw threading yet. If no one else gets around it, I might eventually attempt it myself.