Strange disk quota's behavior with GPOs

Hi all !

Here's my problem :
I setting up disk quota's policy via GPOs on all NTFS partitions of all my win2k servers. Parameters are:
- Disk Quotas enabled,
- Disk Quotas enforced,
- No Quota limit,
- No Warning level,
- Apply policy to removable media.

When this GPO is applyed and when i go to disk C: properties /quotas, all is ok. But when i go to other NTFS partioned disk (D, E and F ) nothing is checked and all options are grayed. On all server it's the same thing, it's going ok only for %systemdrive%.
GPResult on those servers says that all is ok (see below...). What am i doing wrong ?
Any quick help / suggestion are welcome
PL

PS : gpresult gives :
===============================================================
The computer received "Microsoft Disk Quota" settings from these GPOs:

Domaine complet
Revision Number: 151
Unique Name: {31B2F340-016D-11D2-945F-00C04FB984F9}
Domain Name: ************.com
Linked to: Domain (DC=************,DC=com)

Serveurs
Revision Number: 90
Unique Name: {2D4487FE-401B-4A14-8613-2CA55C253920}
Domain Name: ************.com
Linked to: Organizational Unit (OU=Serveurs,OU=Matériel,DC=************,DC=com)

Disk Quotas enabled: Yes
Disk Quotas enforced: Yes
Quota limit: No limit
Warning level: No limit
Log event when quota limit exceeded: Yes
Log event when quota warning level exceeded: Yes
Apply policy to removable media: Yes