Companies often develop a set of software variants that share some features and differ in other ones to meet specific requirements. To exploit the existing software variants as a Software Product Line (SPL), a Feature Model of this SPL must be built as a first step. To do so, it is necessary to define and document the optional and mandatory features that compose the variants. In our previous work, we mined a set of feature implementations as identified sets of source code elements. In this paper, we propose a complementary approach, which aims to document the mined feature implementations by giving them names and descriptions, based on the source code elements that form feature implementations and the use-case diagrams that specify software variants. The novelty of our approach is its use of commonality and variability across software variants, at feature implementation and use-case levels, to run Information Retrieval methods in an efficient way. Experiments on several real case studies (Mobile media and ArgoUML-SPL) validate our approach and show promising results.