Selected Operational Layers Update or Refresh

Within the ArcGIS Viewer for Flex, when adding new layers to an existing map, the existing layer order gets jumbled. I'm not sure how to add a new layer in the middle of all the other layers without deleting all the layers and then re-adding them to the map service.

Has anyone figured out a way to add a new layer in the middle of an existing map service without getting the layer order messed up? Is there a refresh or update?

Thanks