In a multi-site software development setting, creational and validational activities can be distributed and carried out by separate teams. An example of such a distributed development setup is when a system implemented in site A needs to be validated in a remote site B with regard to the component interaction rules dictated by the system architecture. In the current software engineering practice, support has mainly focused on the software creation paying less attention to the needs of the validation phase, which however is becoming increasingly important due to global software engineering practices. This paper argues that systematic support should be provided to the software validation based on the assumptions used in the software creation using the example of component interactions. Furthermore, the paper presents validational tool support for such a systematic process applied to an industrial project. The findings and experiences of the case study are also reported.