Software Product Line (SPL) Engineering has to deal with interrelated, complex models such as feature and architecture models, hence traceability is fundamental to keep them consistent. Commonly, a traceability schema must be started from scratch from project to project. To avoid that, useful traceability practices to solve day to day problems should be modeled explicitly and kept as part of the traceability knowledge gained, and then organizations can reduce time and effort in implementing traceability in new projects. This paper presents an approach for formalizing and reusing traceability practices in SPL Engineering. Using this formalization approach a traceability metamodel is defined, incorporating the particular traceability practices performed in SPL Engineering. Customized traceability methodologies for SPL projects will be systematically and formally generated from this metamodel. These resulting methodologies will have already incorporated the traceability knowledge proven ...