Creating a NetRestore Image from a InstaDMG .dmg

I've got InstaDMG working. Thanks, it's a great tool. I can take my dmg and using Software Image Utility create a NetRestore Image. This I can move to our NFS server and then net boot a Mac and have it restored from my created image. All very close to what I want. The next step is to remove Software Image Utility from the picture and have a command line way to perform the same operation. Then I can go to the InstaDMG directory and type `make` and my images will get created, changed to NetRestore Images and placed in the proper location on our server. I can't find the command line alternative to the GUI Software Image Utility. Is there a command line tool for that?