Hi N x N,
The Windows App Certification Kit should be used to determine the likelihood of an app passing the certification requirements to be made available in the Windows Store. Failing the Windows App Certification Kit tests could therefore indicate that the App will fail to meet the certification requirements. Also, remember that the tools and software currently available are a pre-beta versions available to developers and could still change and be updated.
You should also post a new thread on of the technical focused forums where there are developer support engineers that can assist you in the best way to design your app. The links to those forums are below.
C# / VB : http://social.msdn.microsoft.com/Forums/en-us/winappswithcsharp/threads
C++ : http://social.msdn.microsoft.com/Forums/en-us/winappswithnativecode/threads