Thanks, filling in my dyndns address helped!
Using {%SERVER_NAME%} included the port (which in my case is not 80, e.g. 9000), resulting in something like rtsp://{WAN_IP}:9000:5554/android.sdp
With the rtsp feed I was only able to play video with vplayer.
A http://{WAN_IP}:8081 stream could be played in the default gingerbread player, after I ran the following java program:
Intent i = new Intent (Intent.ACTION_VIEW);
final String url=”http://{WAN_IP}:8081″;
i.setDataAndType(Uri.parse(url),”video/*”);
startActivity(i);
If, however, I try to open a http://{WAN_IP}:8081 stream from the website (“Go to stream”) it says: “starting download” and “download failed”