Challenges in overlaying custom data over ArcGIS online in Flex , works fine in Arc

[nidhiarora]

I am trying to overlay some data on ArcGIS online base maps.
The coordinate system of my data is WGS 1984. The data is perfectly overlayed with ArcGIS online layer in ArcMap.

But when I try to overlay the same data thru arcgis flex viewer, the data is not overlayed
I have changed the data frame of the data to WGS 1984 Web Mercerator  Auxillary sphere , but still the problem persists.
Followed following  article
http://help.arcgis.com/en/arcgisserver/10.0/help/arcgis_server_dotnet_help/index.html#//009300001571...

Any insight in this aspect will be appreciated.
Regards
Nidhi