Among the several other approaches for gathering software requirements, co-creation is often used. The co-creation approach based on elements of participatory research is aimed at involving the end users during the requirements elicitation process. While this approach has many merits, certain limitations need to be addressed. Two limitations include (i) limitations induced due to the subjective judgment of requirements analysts during the analysis and translation of user statements, goals, and desires (gathered during co-creation) into software requirements, and (ii) limitations induced due to varying abilities of different users to conceptualize the systems being developed during early phases of the system development lifecycle, specifically during the co-creation workshops conducted for requirements gathering. To address these limitations the paper proposes a three-step task model-based approach for validation and refinement of requirements generated through co-creation. To instantiate the approach, the paper also presents an illustrative case study featuring the development of a novel electronic identity (e-ID) scheme.