Centos 5 install. Partion order

I can't control the partion order during install.

For example i need.

 
hda5   /var 1GB
hda6  /opt  2GB

I created them in such order but OS adjust them to

 
hda5  /opt  2GB
hda6   /var 1GB

It is frustrating during install, I pretty sure I can order the partion as i like using Fdisk after install.