Why not do it properly through the project options? The CBP file is not intended to be modified manually. Please use C::B to do so.
It was easier to look at the CBP to have a good idea where the problem was.
I tried by right-clicking on the Project, deselecting the prefix auto-generate click-box, setting the correct name and going into "Pre/Post Build step" and changing the "libExample.so" to "Example.so" and it worked.
For what I can see, the wizard is setting the auto-generate to a default value that is preventing the plugin to be generated with the correct filename.
I tried with an already existing plugin (MiniDoc) and it's building and loading fine.
Do you want me to open a bug for this ?