How to transform log4net config like web.config?

From my .csproj file:

<Content Include="log4net.config">
  <SubType>Designer</SubType>
</Content>
<Content Include="log4net.Release.config">
  <DependentUpon>log4net.config</DependentUpon>
</Content>
<Content Include="log4net.Debug.config">
  <DependentUpon>log4net.config</DependentUpon>
</Content>
<Content Include="log4net.Live.config">
  <DependentUpon>log4net.config</DependentUpon>   
</Content>
<Content Include="log4net.Demo.config">
  <DependentUpon>log4net.config</DependentUpon>   
</Content>  

At the bottom of my .csproj file:

  <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
  <Import Project="$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v10.0\WebApplications\Microsoft.WebApplication.targets" />
    <Target Name="AfterCompile" Condition="exists('log4net.$(Configuration).config')">
      <TransformXml Source="log4net.config"
        Destination="$(IntermediateOutputPath)$(TargetFileName).config"
        Transform="log4net.$(Configuration).config" />
      <ItemGroup>
        <AppConfigWithTargetPath Remove="log4net.config"/>
        <AppConfigWithTargetPath Include="$(IntermediateOutputPath)$(TargetFileName).config">
          <TargetPath>$(TargetFileName).config</TargetPath>
        </AppConfigWithTargetPath>
      </ItemGroup>
    </Target>

From log4net.config

<connectionString name="ConnName" 
value="Data Source=localhost\sqlexpress;Initial Catalog=localdb;Persist Security Info=True;Integrated Security=SSPI;" />

From log4net.Live.config (removed sensitive data)

<?xml version="1.0" encoding="utf-8"?>
<configuration xmlns:xdt="http://schemas.microso