In a model-driven development context, the definition (or selection) of an appropriate modeling language is a crucial task. OMG, in the model-driven architecture specification, recommends the use of UML for model-driven developments. However, the lack of semantic precision in UML has led to different model-driven approaches proposing their own domain-specific modeling languages in order to introduce their modeling needs. This paper focuses on customizing the UML association in order to facilitate its application in model-driven development environments. To do this, a well-defined process is defined to integrate the abstract syntax of a domain-specific modeling language that supports a precise semantics for the association construct in UML by means of the automatic generation of a UML profile. Finally, a brief example shows how the results obtained by the application of the proposed process can generate software products through a real model compilation tool.