Cannot override Agelimit settings placed on public folder DB

I have an elaborate Public Folder tree structure, including subfolders with mails and several contact lists. The PF database is set to delete objects after 40 days. The contact lists are individually set so that the “Age limit for replicas” field is 20000 days, as seen on the printout sample          :

Name                  : ΓΕΔ Αλληλογραφία

AgeLimit              :

UseDatabaseAgeDefaults : True

Name                  : Προμηθευτές

AgeLimit              : 20000.00:00:00

UseDatabaseAgeDefaults : False

............................

Yet the override does NOT seem to work, and I keep on loosing the contact entries that are older than 40 days. The same model worked perfectly on Exchange 2003. Please help!