installation dirs on debian

Hi, Just starting with freeradius. I'm confused about installation directories. I'm trying to install freeradius on debian stable. When I install using apt-get (installs 1.0.2 currently), I get freeradius installed in /etc/freeradius. When I install the same version using the tar.gz it gets installed in /usr/local/etc/raddb/ Why is that? The docs show me that /etc/freeradius is the new installation dir. If I want to use the tar.gz and compile myself, do I have to change the dir's by hand or is there an easier way to do this? I've looked into the debian directory in the tarball, but it doesn't learn me anything about this. Can someone point me to the right direction? Many tnx yves