How do I create links from the middle of 1 PDF to another?

The question has been asked before (in 2013!), but is still marked unanswered. So, once again:

I have a FM book, let's call it "Basics", which should include a lot of references to a PDF doc (which is NOT FM-based), let's call it "Supplement.pdf". When I print "Basics.book" to "Basics.pdf", I can add so-called deep links from "Basics.pdf" to "Supplement.pdf" using Acrobat DC. No Problem with that, but when I update "Basics.book" and have to produce "Basics.pdf" once again, all the linking gets lost, of course.

So, all I want to do is place these links in the FM documents included in "Basics.book" and propagate them to "Basics.pdf". According to a sample table entry on the Adobe FM web help, the gotolink syntax of FM should support named targets. But apparently it doesn't, since the referenced document always opens on the first page, and not on the page the target refers to.

I'm using FM 2015 (structured), and yes, the target I'm trying to refer to does exist in the other PDF file, and yes, I know it's case-sensitive (I simply copied its name from the target PDF to the FM Dialog box to avoid a typo).

Any suggestions how i could proceed?