I tried what MalacPoc suggested, but it did not work for me. At the momeent my playthrough seems to be a total chaos, I don't know if I got the guts to start from that early on again.
I thought I just leave that nice battle out and go on, but them Shadowheart turned against me when I did not want to kill the Nightsong, we had to fight and kill Shadowheart. What a mess!