Problem with First-Person-Control and Quaternion.Lerp

Hello!

I am working on a script based on the Android FirstPersonControl script. I recently added a feature that is supposed to simulate the head movement while walking sidewards. I did so using Quaternion.Lerp and it instantly did what it should: The camera is rotated around the z-axis by up to 5 degrees, depending on the position of the move joystick:

 var fromRotation = cameraPivot.rotation; 
 var toRotation = Quaternion.Euler( 0, 0, -moveTouchPad.position.x * 5);
 cameraPivot.rotation = Quaternion.Lerp(fromRotation,toRotation,Time.deltaTime * 5);

But now the look-around part of the script is somehow affected: I can't look around 360 degrees anymore but just about 170 degrees and as soon as I release the rotate touchpad the camera (or the whole player) snaps back to the start rotation that is totally fixed somehow. In my understanding the code lines above should only affect the z-rotation while all other stay untouched.

What am I doing wrong? Please help me, thx

whole update():

 function Update()
 {
     var movement = thisTransform.TransformDirection( Vector3( moveTouchPad.position.x, 0, moveTouchPad.position.y ) );
 
     // We only want horizontal movement
     movement.y = 0;
     movement.Normalize();
     
     // Check for sprinting
     if (rotateTouchPad.tapCount >= 2)
     {
         isSprinting = true;
     }
     else if (!rotateTouchPad.IsFingerDown())
     {
         isSprinting = false;
     }
 
     // Apply movement from move joystick
     var absJoyPos = Vector2( Mathf.Abs( moveTouchPad.position.x ), Mathf.Abs( moveTouchPad.position.y ) );    
     if ( absJoyPos.y > absJoyPos.x )
     {
         if ( moveTouchPad.position.y > 0)
         {
             if ( isSprinting )
             {
                 movement *= sprintSpeed;
             }
             else
             {
                 movement *= forwardSpeed * absJoyPos.y;
             }
         }
         else
         {
             movement *= backwardSpeed * absJoyPos.y;
         }
     }
     else
     {
         movement *= sidestepSpeed * absJoyPos.x;
     }        
     
     
     movement += Physics.gravity;
     movement *= Time.deltaTime;
     
     // Actually move the character    
     character.Move( movement );
     
     
     // Apply rotation from rotation joystick
     if ( character.isGrounded )
     {
         var camRotation = Vector2.zero;
         
         if ( rotateTouchPad )
             camRotation = rotateTouchPad.position;
         else
         {
             // Use tilt instead
 //            print( iPhoneInput.acceleration );
             var acceleration = Input.acceleration;
             var absTiltX = Mathf.Abs( acceleration.x );
             if ( acceleration.z < 0 && acceleration.x < 0 )
             {
                 if ( absTiltX >= tiltPositiveYAxis )
                     camRotation.y = (absTiltX - tiltPositiveYAxis) / (1 - tiltPositiveYAxis);
                 else if ( absTiltX <= tiltNegativeYAxis )
                     camRotation.y = -( tiltNegativeYAxis - absTiltX) / tiltNegativeYAxis;
             }
             
             if ( Mathf.Abs( acceleration.y ) >= tiltXAxisMinimum )
                 camRotation.x = -(acceleration.y - tiltXAxisMinimum) / (1 - tiltXAxisMinimum);
         }
         
         camRotation.x *= rotationSpeed.x;
         camRotation.y *= rotationSpeed.y;
         camRotation *= Time.deltaTime;
         
         // Rotate the character around world-y using x-axis of joystick
         thisTransform.Rotate( 0, camRotation.x, 0, Space.World );
         
         // Rotate only the camera with y-axis input
         cameraPivot.Rotate( -camRotation.y, 0, 0 );
         
         // Apply head movement while walking/sprinting
         
         var fromRotation = cameraPivot.rotation; 
         var toRotation = Quaternion.Euler( 0, 0, -moveTouchPad.position.x * 5);
         cameraPivot.rotation = Quaternion.Lerp(fromRotation,toRotation,Time.deltaTime * 5);
     }
 }