In recent years, business process models are used to define security properties for the corresponding business information systems. In this context, a number of approaches emerged that integrate security properties into standard process modeling languages. Often, these security properties are depicted as text annotations or graphical extensions. However, because the symbols of process-related security properties are not standardized, different issues concerning the comprehensibility and maintenance of the respective models arise. In this paper, we present the initial results of an experimental study on the design and modeling of 11 security concepts in a business process context. In particular, we center on the semantic transparency of the visual symbols that are intended to represent the different concepts (i.e. the one-to-one correspondence between the symbol and its meaning). Our evaluation showed that various symbols exist which are well-perceived. However, further studies are necessary to dissolve a number of remaining issues.