Can't chmod a mounted fat disk

Hello, I followed the guide to install Debian on the Dockstar and I want to thank you all guys for the great work. I'm still quite noob, so please forgive me if I'm asking a silly question but I've been searching around a lot and read man pages but I can't find the answer.

I have installed transmission torrent client, and the demon starts from /etc/init.d as "debian-transmission" user (group is "debian-transmission"). When I try to download a file, it stops with error "Permission denied" with the path of the file.
It looks like the user "debian-transmission" does't have the permission to access that folder, because if I run transmission as root everyting works OK.

That destination folder is an external usb HDD formatted in FAT32 and mounted with autofs. I read that FAT32 doesn't support group permissions, and that should be the reason why I can't CHMOD or CHOWN the folder to "debian-transmission".
I tried to edit "/etc/auto.master"as someone suggested, but it looks like I can't get it right. Here is the autofs conf line:

Quote

/media /etc/auto.removable --timeout=180,defaults,sync,nodev,nosuid,users,umask=000

and here is the "/etc/auto.removable":

Quote

bckhd1 -fstype=auto :/dev/disk/by-label/HITACHI

What steps should I take now?
Thank you all
Best regards

I think I've tried almost all Autofs options, but I still cant't figure this out.... Can someone help me please? :(

It is impossible to chmod files on file systems which have no ownership attributes. You can only set this for the whole file system at mount time.

I don't know if there is an autofs specific problem, but the mount options for setting the ownership information which are used for all files on file systems that don't support per-file/folder ownership information are uid=value and gid=value, where the values are the numeric IDs of the user and group. These parameters and more are described in the mount man page under "Mount options for fat".