[Freeswitch-users] Error msg "Invalid codec VP8!

Hi All, I'm using the actual freeswitch on Ubuntu in version 1.7.0+git~20150807... I added the VP8 codec in the vars.xml for global_codec_prefs and for outbound_codec_prefs. WS on Port 5066 is enabled and I use the "sipml5 demo client" as client. Normal audio calls works successfully (opus) but I get the error message in the CLI " [ERR] switch_core_codec.c:665 Invalid codec VP8! [ERR] switch_core_media.c:2671 Can't load codec? Mod_vp8 is build and in the modules.conf.xml enabled What can I do that the freeswitch allow the VP8 Codec with SIP? Thanks a lot!