Same way as jsmorley and dvo said, I'm not sure what would you like to rotate. The [Meter] image meter? If so, there is no need of an image, because that meter uses just SolidColor, so you can simply rotate it, eg using a TransformationMatrix option. Add the following option to the [Meter] meter (without removing or modifying the existing options):
This TransformationMatrix also requires the DyanmicVariables=1 option, also posted above. It works if you define the following variables in the [Variables] section of the skin:
Angle is the rotation angle, in degrees. Note that positive value rotates the image anticlockwise, while a negative value rotates it clockwise.
CenterX and CenterY are the coordinates of the center of rotation, relatively to the image (very important). This means that if you want to rotate the image around its own center, you have to set the two variable to CenterX=220 and CenterY=220, because the size of the image is W=440 and H=440. Dividing these values by 2, you get the mentioned coordinates for the center of rotation.
Please let me know if this meats your needs and if it doesn't, what have I mistaken.