The .Net assemblies provided in the DLLs described here are accessible from COM. THis should allow you to, for example, write VBA code which utilises MPXJ functionality. To assist with this, type libraries in the form of TLB files are provided in the directory for each of the DLLs distributed with MPXJ. You will also need to register the MPXJ assemblies in order to use them from COM, using the regasm assembly registration tool. For your convenience two batch files have been provided in the directory: mpxj-register-assemblies.bat and mpxj-unregister-assemblies.bat. These batch files will register and unreigster the MPXJ assemblies respectively. These batch files assume that regasm is available on the path.