I think I have understanding problem....
I have created a small trackerless testtorrent and used router.bittorrent.com:6881 as standard node. After I created a new environment for ktorrent (aka fresh install without any old configuration), I started ktorrent, set up all configuration and added the torrent....and nothing happened
KTorrent didnt ask the default node for nodes and so nothing will ever happen

After testing a little bit I noticed, that I can get a PORT packet from a locally installed bittorrent. KTorrent will ask that bittorrent for new peers and everything will start to run....

I also tried to add the torrent to ktorrent and bittorrent. Both know about each other (ktorrent because it got the PORT packet from local bittorrent) and none of them will start (none of them has the data). So I copied the data to the ktorrent directory and made check data integrity and ktorrent noticed I have "downloaded" everything....but bittorrent cannot download anything. It only starts when I restart ktorrent (manual announce doesnt seem to do anything).

I dont have the time to check the code. So hopefully the description helps to find the problems.

I think I know where the problem is, me misunderstanding the DHT spec.