In 3.0 they removed lots of classes and members
In api 3.0 I am not even able to write even simple marker symbol
I am using esri.prototypelab.shy (http://www.arcgis.com/home/item.html...1d308fde43cd3c)
for setting effect in base map and i noticed it supports silverlight 3 and silverlight 4 but it doesn't support silverlight 5.