external NTFS disk ftp access

[blmain]

Hi

My system is based on Ubuntu Server 9.04
For a more confortable use, I installed Ubuntu Desktop
I have External USB Disk NTFS format
I installed VSFTPD as FTP server

When anonymous user try to acces to those external disk everything is ok

Those external disk are with owner / group as root

I migrate to Ubuntu 9.10 with the command do-release-upgrade
Suppose that both server and desktop are migrate

So, now, when anonymous user try to access to those exteral disk, the access is denied
I checked the externisk owner / group, they are no more as root but as myself
So, I understand the access denied but how to do to allow again anonymous user to access to those disk ?
I try to change the owner / group as root, buty nothing change. They stay as myself

Thanks for your help