bird6.conf & Router ID

Hi all, just a quite stupid question but I'm struggling with the bird6 configuration. I want to configure the router ID as follows: --snip-- router id 2a00:cd0:1000:47::2; --snap-- But the error message "Router IDs must be entered as hexadecimal numbers or IPv4 addresses in IPv6 version" appears. Using an embedded IPv4 address does not work, as well. It is BIRD 1.2.3. Thanks matthias