Flow Arrows for Utilities

Hi,

I am trying to depict the flow of electrical lines in the ArcGIS for Flex Viewer. I have tried creating the flow arrows on the layer itself and also tried adding it as a separate layer. I am using arrow at the end symbology in ArcGIS for Desktop. But when i add the services into the flex viewer they just show as a solid black line, and dont depict direction. Is there something i am missing? The viewer is version 3.6.

Thanks,
Andrew