windeployqt does not find Qt dlls in VS project setup

I have an example project here (created with the Qt5 wizard) in Visual Studio 2013, Windows 7 64Bit.
I tried using windeployqt to copy the needed dlls, but failed because it does not seem to find the dlls in the correct path.
Qt is located in "D:\Dependencies\ThirdParty\Qt\Qt-5.3.2\x64". It was not installed there, but its bin\qt.conf Prefix is "../", so it does work fine.
When I try to copy the Qt dlls in a pos-build step, I do the following:

"$(QTDIR)\bin\windeployqt" --dir "$(QTDIR)" --release --dry-run --verbose 2 "$(TargetPath)"

The are 2 problem with this:

1. -debug/-release:
This is very inconvenient in VS, as the $(Configuration) flag is "Debug" or "Release" and there is afaik no possibility to lowercase the string, thus different rules are needed...
I see readPeExecutable stating "debug: 1". Is the flag even needed?

2. It simply does not work. The output is:
1> testprojekt.vcxproj -> C:\Projekte_2013\testprojekt\x64\Debug\testprojekt.exe
1> Qt binaries in D:\Qt\Qt5.3.2\5.3\msvc2013_64_opengl\bin
1> readPeExecutable: C:/Projekte_2013/testprojekt/x64/Debug/testprojekt.exe 64 bit, debug: 1
1> Unable to find dependent libraries of D:\Qt\Qt5.3.2\5.3\msvc2013_64_opengl\bin\Qt5Cored.dll :Cannot open 'D:\Qt\Qt5.3.2\5.3\msvc2013_64_opengl\bin/Qt5Cored.dll': Das System kann den angegebenen Pfad nicht finden.
1>
1>
1>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\V120\Microsoft.CppCommon.targets(132,5): error MSB3073: The command ""D:\Dependencies\ThirdParty\Qt\Qt-5.3.2\x64\bin\windeployqt" --dir "D:\Dependencies\ThirdParty\Qt\Qt-5.3.2\x64" --debug --dry-run --verbose 2 "C:\Projekte_2013\testprojekt\x64\Debug\testprojekt.exe"
1>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\V120\Microsoft.CppCommon.targets(132,5): error MSB3073: :VCEnd" exited with code 1.

I also tried --dir "$(QTDIR)\bin" as the Qt path, but got the same error.