HFS+ can't chown/chmod

I have a drive full of media which I would like to use as a basis for a media server. the drive is Formatted HFS+.

I have the following in my /etc/fstab

/dev/hdd10 /mnt/caterpillah hfsplus rw 0 0

When I mount the partition and do [$ mount | grep hdd] I get:

/dev/hdd10 on /mnt/caterpillah type hfsplus (rw)


However, the disk was obviously part'ed on an osx machine, and suid's and uid's are off (501/80), so I need to change them:

# chown myuser:mygroup /mnt/my_drive
chown: changing ownership of '/mnt/my_drive' : Read-only file system

the same thing happens with chmod. If the drive is mounted r/w, why can't I change permissions or ownership?