i cant try the latest vfat modules for fc6 right now. but it should work i believe.
Is it possible for you to convert /data to NTFS filesystem under your Windows?
If so, the below are tested under my systems and is currently working right now.
after NTFS convertion, just shutdown your windows properly, then go to FC6, issue
#yum install ntfs-3g
reboot. mount your shared drive as
#mount /dev/hda2 /data
walahito! no need to change ownership, you can now read/write to your /data.
this may somehow upgrade your kernel though.
make it permanent with /etc/fstab, edit the lines with vfat and change them to ntfs like so
/dev/hdb2 /data ntfs defaults 0 0
happy linux ntfs!