Although I have never tried to install git
The proper steps would probably be
Edit your sources.file so that the only active sources are the squeeze sources
nano /etc/apt/sources.list
Edit it to look like this
deb http://ftp.us.debian.org/debian/ squeeze main#deb http://ftp.us.debian.org/debian/ sid main#deb http://ftp.us.debian.org/debian/ experimental main
This removes the package references to the firmware
rm -f /var/lib/dpkg/info/wd-nas.*
Then
apt-get update
Then install GIT
DO NOT overwrite the php.ini files and if asked in a blue menu, select to keep existing files
