std::locale ctor fails (L10n with C++)

Hello,

recently I stepped over Strotrup's TC++PL (third ed.) Chapter D.1
where the localization sup****t of the C++ stdlib is explained.
[ http://www.research.att.com/~bs/3rd_loc.pdf
]

Unfortunately the constructor fails if I try to instantiate std::locale
for locales other than C or POSIX.
With (only) LANG="de.DE.UTF-8" set in ENV the following code thows an
exception:
std::locale loc("");

and std::setlocale(LC_ALL, ""); works fine?!

My GCC Version is "gcc (GCC) 3.4.6 [FreeBSD] 20060305" and I'm
using FreeBSD 6.2.

Here's my example code:

#include <clocale>
#include <iostream>

int main()
{
  using std::cout;
  using std::endl;

  const char* const lstr = std::setlocale(LC_ALL, "");

  if (lstr)
   cout << "lstr=" << lstr << endl;
  else
   cout << "lstr=NULL" << endl;

  std::locale loc("");
  cout << "std::locale loc=" << loc.name() << endl;
}

Output:
lstr=de_DE.UTF-8
terminate called after throwing an instance of 'std::runtime_error'
   what():  locale::facet::_S_create_c_locale name not valid
Abort (core dumped)

Does anyone have similar problems ? What am I doing wrong ?
Is the libstdc++ incomplete on my platform?

Sa****