Uploaded shapefile attributes available in Advanced Label Options

One of our users has pointed out that in WebADF they could upload a shapefile, then use the Text markup tool to add text from one or more of the shapefile's attributes.  Basically, the Text tool treated an uploaded shapefile like any of the other layers.

Some of our users have requested that same ability in the Silverlight Viewer.  In other words, they would like uploaded shapefiles to appear as available layers in the "Add Feature Label" dropdown when using "Advanced Label Options". 

Thanks,

Steve