If you need FreeRadius with EAP/TLS support in Debian Stable (sarge), then look at this page where you can get a proper patch to enable it: http://www.wapu.org/projects.php?id=freeradius-eaptls. I have made those changes myself but using mentioned patch should be quicker than editing debian/rules, debian/control and installing libssl-dev manually.
All of this of course was founded by ``uncompatibility in some FOSS licences'', as always (see this post on debian-user).
Ahm, and perform this on the console:
echo "freeradius hold" |dpkg --set-selections
to not get surprised after next apt-get update && apt-get upgrade ;-)