Vista - ADsSecurity and Inheritance

I've been using the ADsSecurity.dll to query and modify permissions on a
Windows Server file system (NTFS).

If I reconfigure the permissions on a folder they aren't inherited by the
subfolders and files even though the permissions say they are for "This
Folder, Subfolders and Files". If I check the subfolder themselves the
permissions remain unchanged even though the "inherit from parent" checkbox
is checked. Is there a way to refresh the Security Descriptor for subfolders
and files so that they are tally with the dialog and ARE inherited from the
parent folder?

The alternative method I've found is to recurse all subfolders and files and
apply the same permissions. Works fine, but I'd far prefer them to be set to
inherit in case someone amends the permissions on the parent at some stage in
the future and forgets to apply to subfolders and files.

Any advice would be much appreciated.