Wrong connection strings returned - asp.net

Question

I've written a WCF service application.
When the project is generated, visual studio creates 3 web config files.
I've finished the project and to date I've been using a hard coded connection string within my GetOpenConnection() function, so I now want to move the connection string to the web.config files.
The following call returns null.
ConnectionStringSettings csSettings = ConfigurationManager.ConnectionStrings["PulseWcfConnectionString"];
When I run the following code it doesn't return the string set in my web.debug.config file.
for(int idx = 0; idx < ConfigurationManager.ConnectionStrings.Count; idx++)
Debug.WriteLine(ConfigurationManager.ConnectionStrings[idx].ConnectionString);
it returns the following 2 items, 2nd one is an empty string. I don't recognise the first line, maybe it's a default one?
data source=.\SQLEXPRESS;Integrated Security=SSPI; AttachDBFilename=|DataDirectory|aspnetdb.mdf;User Instance=true
""
What am I missing please?
My web.debug.config contains the following which should be for a local sql server instance
<?xml version="1.0"?>
<!-- For more information on using web.config transformation visit http://go.microsoft.com/fwlink/?LinkId=125889 -->
<configuration xmlns:xdt="http://schemas.microsoft.com/XML-Document-Transform">
<connectionStrings>
<add
name="PulseWcfConnectionString"
connectionString="Data Source=WIN8-CLAIRE\SQLSRVDEV2008;Initial
Catalog=gcll;Persist Security Info=True;Integrated Security=True"
providerName="System.Data.SqlClient"
/>
</connectionStrings>
</configuration>
For now my web.release.config contains the same thing (it's being published to it's destination tomorrow so I'll change the details for it then)
<?xml version="1.0"?>
<!-- For more information on using web.config transformation visit http://go.microsoft.com/fwlink/?LinkId=125889 -->
<configuration xmlns:xdt="http://schemas.microsoft.com/XML-Document-Transform">
<connectionStrings>
<add
name="PulseWcfConnectionString"
connectionString="Data Source=WIN8-CLAIRE\SQLSRVDEV2008;Initial
Catalog=gcll;Persist Security Info=True;Integrated Security=True"
providerName="System.Data.SqlClient"
/>
</connectionStrings>
<system.web>
<compilation xdt:Transform="RemoveAttributes(debug)" />
</system.web>
</configuration>
web.config
<?xml version="1.0"?>
<configuration>
<system.web>
<compilation debug="true" targetFramework="4.0" />
<authentication mode="Windows" />
</system.web>
<system.serviceModel>
<services>
<service name ="pulse.smartcentre.wcf.service.app.PulseWebService"
behaviorConfiguration="ServiceBehavior">
<host>
<baseAddresses>
<add baseAddress = "http://localhost:52478/Design_Time_Addresses/pulse.smartcentre.wcf.service.app/PulseWebService/" />
</baseAddresses>
</host>
<endpoint address="" binding="wsHttpBinding"
bindingConfiguration="wsHttpBinding"
contract="pulse.smartcentre.wcf.service.app.IPulseWebService">
<!--
Upon deployment, the following identity element should be removed or replaced to reflect the
identity under which the deployed service runs. If removed, WCF will infer an appropriate identity
automatically.
-->
<identity>
<dns value="localhost"/>
</identity>
</endpoint>
<!-- Metadata Endpoints -->
<!-- The Metadata Exchange endpoint is used by the service to describe itself to clients. -->
<!-- This endpoint does not use a secure binding and should be secured or removed before deployment -->
<endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange"/>
</service>
</services>
<!-- CNH -->
<bindings>
<!-- Secure binding (to use) -->
<wsHttpBinding>
<binding name="wsHttpBinding" closeTimeout="00:01:00"
openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:10:00"
allowCookies="false" bypassProxyOnLocal="false" hostNameComparisonMode="StrongWildcard"
maxBufferPoolSize="2147483647" maxReceivedMessageSize="2147483647"
messageEncoding="Text" textEncoding="utf-8"
useDefaultWebProxy="true" transactionFlow="true">
<readerQuotas
maxArrayLength="2147483647"
maxBytesPerRead="2147483647"
maxDepth="2147483647"
maxNameTableCharCount="2147483647"
maxStringContentLength="2147483647" />
</binding>
</wsHttpBinding>
</bindings>
<behaviors>
<serviceBehaviors>
<behavior name="ServiceBehavior">
<dataContractSerializer maxItemsInObjectGraph="2147483647"/>
<!-- To avoid disclosing metadata information, set the value below to false and remove the metadata endpoint above before deployment -->
<serviceMetadata httpGetEnabled="true"/>
<!-- To receive exception details in faults for debugging purposes, set the value below to true. Set to false before deployment to avoid disclosing exception information -->
<serviceDebug includeExceptionDetailInFaults="true"/>
</behavior>
</serviceBehaviors>
<endpointBehaviors>
<behavior name="Behaviors.EndpointBehavior">
<dataContractSerializer maxItemsInObjectGraph="2147483647" />
</behavior>
</endpointBehaviors>
</behaviors>
<serviceHostingEnvironment multipleSiteBindingsEnabled="true" />
</system.serviceModel>
<system.webServer>
<modules runAllManagedModulesForAllRequests="true"/>
</system.webServer>
</configuration>

Answer 1

If you use the transformation files, you need to add the transformation property, and specify what you would like to do, Insert, Remove, Replace...
I use to put the local connection in the master web.config and then transform it in the Release configuration, by Replacing the attributes of the defined connection string.
Check this article: Web.config Transformation Syntax for Web Project Deployment Using Visual Studio
If you want to use your way, just add xdt:Transform="Insert" in the <add> node.
You can test your transformation using this web tester: Web.config Transformation Tester