Thank you for your interest in NORMA. There are several approaches here ranging from direct NORMA integration to installation of your own Dataphor-specific extensions handled as an add-on to NORMA.
I had not heard of Dataphor until this post, but they appear to be located a few miles south of my location. Are you associated with the company, or an external power user?
Adding generation transforms is pretty straightforward and can be done without a full NORMA build. These aren't really DIL, which is an XML language that represents traditional SQL (DDL and DML) constructs. So, a D4 generator would go in its own directory.
(For the casual reader, the rest of these is boringly technical. We should take details beyond this off line).
The VS2012 build process should run as described in the README.txt file in the source root directory. The development builds are designed to run in the standard Visual Studio Experimental environment (devenv.exe /rootsuffix exp). While you can easily attach and debug a setup-installed NORMA from the source tree, I strongly recommend against trying to build the project with a setup install already in place, unless you enjoy hand-cleaning the global assembly cache (GAC).
The sourceforge repository is mirrored off of a private repository, I don't use it for live development.
To build, you need the prerequisites (VS2012 Pro, VSSDK, DSL Tools SDK, PLiX installer that comes with NORMA). This should let you run FirstTimeBuildVS2012.bat from a VS2012 command prompt (as administrator recommended). This runs the BuildDevTools.bat and Build.bat files for VS2012. I've seen odd build error ordering issues with BuildDevToolsVS2012.bat, just keep running it until it runs cleanly (I know this doesn't sound encouraging, but this only needs to be run once per the lifetime of a machine). After the devtools build cleanly, BuildVS2012.bat /t:Rebuild will give you a clean build of the rest. I do not recommend the BuildAll*, BuildTests*, or BuildSetup* variants as these need significantly more stuff. The magic environment variable for VS2012 is TargetVisualStudioVersion=v11.0. This needs to be set before opening any of the *VS2012.sln files.
Do not run the regen all files in a solution. This regenerates all of the PLiX files (my XML-based code generation system), plus all of the DSL-generated files (the T4 templates shipped with the DSL toolkit). I've had to make several changes to the stock DSL generators to handle everything from naive handling of 1-1 relationship handling to valid XML doc comment generation. However, these templates are not open source and I do not have the rights to post them publicly, so you'll need to get them from me privately. I also haven't tried the VS2012 DSL generators (the 2005 code works for 05 and 08, 2010 works for 2012) and don't have the corresponding template tweaks, so I guess I'm not 100% build capable on VS2012 (I also haven't ported all of the testing bits to all platforms).
Having said all of that, you don't really need to build the full project to install generators. The NORMA code generators are only loosely attached to the designer (one registry entry to add ORMCustomTool to any .orm file in a project, one automation object callback to get a snapshot of the current (potentially unsaved) XML, and another automation object callback to turn on required extensions). (Sorry, this is far from obvious) All of the generators are installed when the ORMCustomTool generator is built, which calls Tools\ORMCustomTool\Install.bat. The easiest approach to add your own extensions is to just copy that file and blow away most of it. The 'setupenvironment' call at the top is important. You can also edit the SetupEnvironment.bat file to install against the main VS branch instead of a debug build (search for Exp in that file).
The .sln files under the XML directory are for convenience and are not part of the build.