try this: (substitue user:group)
========
sudo chown -R user:group /mnt/home2

Then see if you can create files on the /mnt/home2

If so, reboot and see if it mounts with your user:group and you can still
read/write to /mnt/home2

check user:group using ls -l:
============================
ls -l /mnt/home2

If problems persists, I will check my machine at home as I did mounted an
ext3 partition for a similar purpose a week ago.