An advanced high-level approach for programming of real-time distributed computing applications, the TMO (Time-triggered Message-triggered Object) programming and specification scheme, has been enabled without creating any new language or compiler. Instead, a middleware system named the TMO Support Middleware (TMOSM) and an API that wraps around the execution support services of TMOSM have been established. An approach enabling further reduction of the labor in TMO programming is to let the programmer use a GUI to build structural frames of application TMO networks. The supporting tool called the Visual Studio for TMO (ViSTMO) consists of a GUI part for interactive design of TMO-network structures and a part for automated generation of C++TMO code-frameworks. The TMO scheme contains mechanisms enabling efficient design of autonomy-rich structures of application systems and ViSTMO provides GUIs for programming the use of those mechanisms among others. The recent expansion and refinement of the functionality of and the implementation techniques used in ViSTMO are discussed in this paper.