I have successfully added a service reference to my Visual Studio 2013 project.
I cannot however reference it in code.
For example, given the project name "myproject", and the service reference name "thirdpartyasmx", I cannot use this using directive...
using myproject.thirdpartyasmx
I cannot instantiate the class directly either...
thirdpartyasmx test = new thirdpartyasmx();
I have tried building the solution before trying to reference the service reference.
This is not something I do regularly, so I'm afraid I'm missing a step.
UPDATED based on OP feedback
When you click on Add Service Reference, click on the Advanced button in the bottom left of the dialog box:
Clear the Reuse types in referenced assemblies checkbox (by default it's checked).