Hi Pierre,
What version of AtoM are you using? I noticed that you've linked to the 2.0 documentation - though we currently have a 2.4 release available, and are preparing a 2.4.1 bug fix release currently. Can you please check the full version included in Admin > Settings, at the top of the page?
If the site is publicly accessible, sending a link so that I can take a look would be very helpful!
I think there may also be a translation issue - can you please tell me what you mean by "notices"? Do you mean archival description reports? Currently in AtoM, those reports are flat - that is, they don't include heirarchical information about parents. The File report will only include file-level descriptions, and the Item-level report will only include the items, regardless of where they are in the hierarchy.
If you are using a later version of AtoM such as 2.3 or 2.4, then you might consider using the Finding aid generation instead. I think this will give you more of what you're looking for. See:
The download button that you are seeing in the link from our demo site is how Finding aids are made available to public users in the 2.4 release. I suggest that you consider upgrading to the latest version - it sounds like this might meet your needs.
Regards,