Pure orientation on tf tree

Hello,

I would like to read the orientation of my 3DM-CV7-AHRS from a tf topic or a pose publisher. I followed the wiki and tried the following config for my ros node:

tf_mode: 2

[...]

filter_relative_position_config : False
filter_relative_position_frame  : 2
filter_relative_position_source : 2
filter_relative_position_ref    : [0.0, 0.0, 0.01]

According to the wiki (https://wiki.ros.org/microstrain_inertial_driver/transforms, section 2.3), this should now publish a static tf from earth_frame_id -> map_frame_id (this is working), and a dynamic tf from map_frame_id -> target_frame_id (this is not working). Am I missing something? Do i need to somehow fake odometry in order to have a 'valid' full pose for the tf tree? I do not care about the position, only the orientation.

Thanks in advance.