Rotation using orientation

Hi,

I am trying for some weeks to define the rotation of a mesh body using its orientation.
I have a list with the data for the orientation (euler angles) in different time steps. I know that I need to find the angular velocity necessary to change the orientation. I am using the formula that I found here: http://mathworld.wolfram.com/EulerAngles.html
How can I adapt it to yade, as I need to calculte the rotation axis and the scalar value of the angular velocity? Is the rotation axis just the orientation that will be change? Or should I obtain it from the formula above?
I would be very glad if someone could help me.

Thanks in advance. Daniela.