1. A computer-readable storage medium holding computer-executable instructions for creating a bus signal in a graphical modeling environment, the instructions when executed on a processor cause at least one computing device to: interact with a graphical model in the graphical modeling environment, the graphical model including a plurality of modeling domains; provide a first and second data signal in the graphical model, the first and second data signal located in a first modeling domain that is one of the plurality of modeling domains; combine the first data signal and the second data signal together to form a bus signal in the graphical model, the bus signal located in the first modeling domain; and pass the bus signal to a non-virtual model component in a second modeling domain that is another one of the plurality of modeling domains in the graphical model, the second modeling domain differing from the first modeling domain.