A guide to Using multiple backup drives with Time Machine:

http://spyder.wordpress.com/2008/02/16/using-multiple-backup-drives-with-time-machine/

Instructions for manually installing mod_rewrite on the QNAP:

http://forum.qnap.com/viewtopic.php?f=32&t=3512&hilit=apache+mod_rewrite

To show all files (including hidden files) in Finder, type this in the Terminal (Applications/Utilities/):
defaults write com.apple.Finder AppleShowAllFiles YES

To revert back to not showing hidden files:
defaults write com.apple.Finder AppleShowAllFiles NO

…and relaunch Finder.