Adobe Acrobat isn't designed for the use in a scheduled task.
According to what I have found on this (including this thread which you've already found), what you are trying to do is exactly how acrobat is supposed to work with bpdx files, so Bernd's post is incorrect on this point. I haven't found a way of doing it yet but will get back to you if I am lucky.
The catalog/index scheduled update is not part of Acrobat "Batch Process" or "Action". The running of rebuilding of the catalog/index is controlled by the values within the BPDX file. So if one opens the BPDX file with Acrobat and a catalog/index is scheduled to be rebuilt or past the scheduled date and time, then the catalog/index build is submitted for precessing by Acrobat..
It is also possible to open an FDF file and add/run JavaScirpts within a PDF, and again this is different than running a "Batch Process"/"Action" in Acrobat.