[libtorrent] Can't get metadata from *some* magnet links

[Nemanja B. <4b...@gm...>]

Hello,

I'm using libtorrent in a small application, and I am encouraging 
problems with download from magnet links - some of they simply
doesn't work (I've tried in uTorrent, and metadata is properly downloaded).

Simply, th.has_metadata() is always returning false for me. I've started 
DHT before calling add_magnet_uri

ses.add_dht_router(std::make_pair(std::string("router.bittorrent.com"), 
6881));
     ses.start_dht();

but I've got nothing.

Example link that don't work (it is Linux Mint torrent):

magnet:?xt=urn:btih:F2M5S7YXNBSEVBVI5GN73AGICZEQ7FM3

and one that does work is:

magnet:?xt=urn:btih:a5f38328423c1eb8e88948756894cab991b31637&dn=Linux+Mint+13+KDE+%2832-bit%29&tr=udp%3A%2F%2Ftracker.openbittorrent.com%3A80&tr=udp%3A%2F%2Ftracker.publicbt.com%3A80&tr=udp%3A%2F%2Ftracker.istole.it%3A6969&tr=udp%3A%2F%2Ftracker.ccc.de%3A80


Could you simply point me out what I could be mistaking? For some 
reason, client_test.exe application with there parameters don't start 
downloading - only unchoke counter is increasing in negative direction 
(decreasing).


Thank you,
Nemanja