Best way of injecting application configuration

Well, I'm making my foray into this fantastic site with a question about the correct way to inject configuration settings into application components. So, the overview is : I have an application written in C# .Net 3.5. It consists of 3 assemblies - a Core, a Data and a Service. The data & service assemblies require settings retrieved from the app.config, which is done via a settings file, eg.

Code :

public static String RequestQueueConnectionString
{
    get { return ConnectionSettings.Default.RequestQueueConnectionString; }
}

Config :

<applicationSettings>
  <MyNamespace.Data.ConnectionSettings>
    <setting name="RequestQueueConnectionString" serializeAs="String">
    ...

Now, the assemblies are all setup using StructureMap for IoC - which to my mind should provide the answer to what I am looking for, but I just can't quite see it!

IoC :

public static void ConfigureStructureMap(IContainer container)
{
    container.Configure(x => ...
    ...

What I want to be able to do is to inject a configuration class already populated into the IoC container such that those settings are used for that assembly, NOT those specified in the settings file / app.config. So perhaps :

public static void ConfigureStructureMap(IContainer container, MyConfigClass config)
{
    container.Configure(x => x.For<DataConfig>()
                              .Singleton()
                              .Use ???
    ...

I hope I have provided enough details here - forgive a newbie if I have not and please let me know what else would be helpful in answering this!