Thank you for the post. The rotation means 3x3 rotation matrix
R = [ r11 r12 r13;
r21 r22 r23;
r31 r32 r33 ];
The best way how to be sure that you have correct understanding is to write a simple script (in Matlab for example) that will visualize you the cameras using data from xmps.
We will release help to this topic as soon as possible.