Bone, Normal Orientation, Roll Handles question


I am new to 3D terminologies, I’m on blender 2.49a, and have a question.

I have successfully created a humaniod mesh with skeleton/armature and animating it without any problems faced.

But I realised that there is this “roll handle” parameter for bones which affect the normal orientation and in turn affect bone tagging programatically when i try to attach say a sword to a hand in graphics engine such as Ogre3d.

What is the usual setting for these paramneters?

For example, why is the first created armature roll = 0 but subsequent extruded armature has roll = 180, making the normal orientation different from local orientation when the armature is verticall head to tail upwards?

I also would love to see this explained, perhaps you should repost this in the animation section under support