.NET AssemblyName per configuration -> always rebuilding

Question

I figured how to change the filename of the output assembly depending on the current configuration:

<PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
    <OutputPath>path-to-debug-output</OutputPath>
    <AssemblyName>myAssembly.Debug</AssemblyName>
</PropertyGroup>
<PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
    <OutputPath>path-to-release-output</OutputPath>
    <AssemblyName>myAssembly</AssemblyName>
</PropertyGroup>

Unfortunately, now everytime I hit "build all" in Visual Studio in debug configuration, it actually rebuilds everything even if no changes were done at all:

1>  myAssembly -> path-to-debug-output\myAssembly.Debug.dll

In release mode I get this message exactly one time, after that "myAssembly" is not build until I do any changes to the code.

I suppose there is some check for existence of the output assembly done (and maybe timestamp checking etc.). Does someone know how I can configure this in my .csproj file (or somewhere else)?

[EDIT]

Here is an example of a full .csproj file with configuration dependent output files: http://pastebin.com/pFj4nxtj