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.
nice; hope it works out for you! I used a dremel with a circle cutter and a cutting bit; these parts (both amazon links, non-affiliate):
It was a little awkward but worked out well enough; the plastic likes to melt up around the bit but if you move steadily enough it works out ok. The tools were what I had on hand; the other thing I considered was a standard hole saw, but I felt like it'd most likely bind up and crack the container.
I intentionally made the gaskets and lip on the mount wide to cover up any ugliness that the cutting might create, and it worked out great. Good luck!