I try to setup a samba file server, but whatever I do I can't get write access to work (reading works fine). This is my current situation:

I have a local fileserver with 3 harddisks mounted at /mnt/share/disk<nr>. 2 of these use the ext4 filesystem, the third one is ntfs. This file server runs Fedora 18 32-bit. The root folders of these harddisks are owned by superman:superman, and testparm outputs the following:

[global]
workgroup = WORKGROUP
netbios name = FILE_SERVER
server string = Samba Server Version %v
interfaces = lo, eth0, 192.168.123.191/8
log file = /var/log/samba/log.%m
max log size = 50
unix extensions = No
load printers = No
idmap config * : backend = tdb
hosts allow = 192.168.123.
cups options = raw
wide links = Yes

[share]
comment = Home Directories
path = /home/share/
write list = superman, @users
force user = superman
read only = No
create mask = 0777
directory mask = 0777
inherit permissions = Yes
guest ok = Yes

I've tried a lot to get this to work: the disk are chmodded to 777, I've tried turning off selinux, I've added the samba_share_t label to the disks and as can be seen in the above output I tried to make the smb config as permissive as I could, but still I cannot write to the share (tried from Windows 7 and another Fedora installation).

What can I try to be able to write to the shares?

EDIT: The replies I got so far are mostly concerned with the smb.conf. I have however tried a lot of different setup, ready made configs, and solutions to similar problems for the smb.conf file, so I suspect that the real problem is somewhere else.