Quick post today.
It seems that application debugging in version 5+ is not an easy task.
What to do to achieve it:
1. Make sure Application pool is in Classic mode, not Managed Pipeline Mode.
2. Make sure you added below highlighted in Red setting in web.config:
<compilation debug="True" defaultLanguage="c#" numRecompilesBeforeAppRestart="9999" targetFramework="4.5.1">
3. Also add this key to web.config into appsettings section:
<add key="UseRuntimeCompilation" value="False" />
4. Make sure you have installed Visual Studio 2012, .NET 4.5.1, and .NET 4.5.1 Multi Targeting Pack
5. No need to install Acumatica Framework :)
6. Create New Extension Library (Dummy One) under Customization Project Editor. This will create a solution link for Visual Studio.
7. Open Visual Studio. Navigate to App_Code/Caches.
Here we are :) Attach to the process and Enjoy.
All the best,