Add operational layer from ArcGIS.com created with ArcGIS desktop

Good day,

I would like to create an operational layer and present it on top of a base map using Viewer for Flex.

I created a map of canadian health regions in ArcGIS desktop and used the "Share" feature which allowed me to upload the map as a package into ArcGIS online.

I thought I could then open Viewer for Flex and add the layer to my map but when I go to Step 2 (Operational Layers) and try to
select a layer from "My Content" in ArcGIS online I find nothing.

How do I create an operational layer and make it available for Viewer for Flex?

Any help would be appreciated.

Thanks in advance.

Erik