One of the new features in the upcoming ASN1C 6.5 release will be a Visual Studio wizard for Windows SDKs. This wizard will allow you to create a Visual Studio 2005 or higher project from the Visual Studio IDE by specifying the .asn or .xsd files for which you want code generated.
The wizard will be invoked from the Visual Studio IDE, and it will run up the ASN1C GUI to allow you to define the project in much the same way that you would use the GUI currently. When you finish using the GUI, it will generate the code and the project file, and the Visual Studio Wizard will load the generated project into your workspace.
The wizard will work for C, C++, and C# projects. In the ASN1C 6.5 distribution there will be a vswizard folder. This folder will contain a README.txt file that describes the steps to take to set up the wizard. Basically the set up involves just editing one file and then copying a few files to the correct place in your Visual Studio installation hierarchy. Once the set up is done, you can invoke the wizard by clicking either Visual C++ or Visual C# in the Visual Studio New Project dialog and then choosing ASN1C as the project template.