Software Factories pose a paradigm shift that promises to turn application assembly more cost eective through systematic reuse. These advances in software industrialization have however reduced the cost of coding applications at the expense of increasing assembling complexity, i.e., the process of coming up with the nal end application. To alleviate this problem, we advocate for a new discipline inside the general software development process, i.e. Assembly Plan Management, that permits to face complexity in assembly processes. A non-trivial case study application is presented.