Software Process Management deals with activities that demand limited resources. The definition of resource allocation strategies is based on characteristics about required resources and their dynamic availability. However, most of existing PSEEs do not allow precise resource specification, and the instantiation is often based on the knowledge and experience of a process designer, mostly without automated support. This situation difficults resource allocation analysis and optimization in process systems and can influence project management and overall software quality. This paper proposes Instantiation Policies as a compact formalism to allow user-defined reusable allocation strategies. The motivations for this solution, the proposed meta-model, language and some application examples for this approach are presented and discussed.