I didn’t quote the signid in the first place.
However: I tried again the long way: signing with XCode (needed to click 8 times “Fix issue”, twice for each target platform). The result is still not loadable. But I can wrap that one, the error of the wraptool is gone in favour of a warning:
Warning! This binary has an invalid existing platform digital signature. This situation could happen if you wrapped a binary that was already signed. Regardless, a new signature will be created now, using your specified credentials.
The certificate is still valid, it expires in october 2016, is my own and didn’t reject or do anything with it, except sign here on my “private” computer. I had no released software yet.
This wrapped plugin I can load in the productive ProTools, but it crashes (and now I can’t debug).
And the development ProTools still rejects any version, unsigned, apple signed, wrapped.
EDIT: as it turns out, it has nothing to do with loading jucer files, except that my confusion started with the leftover build script, I will open a new thread and link this one, sorry for the mess…
EDIT 2: Continuing here: AAX plugins created with 4.2 no longer loadable in ProTools development build