Yes. You should be mapping the stages of your life cycle into RequisitePro. One of the first steps you should be taking while starting your RequisitePro project is creating you Requirement Management Plan where, between other things you will be defining the requirement type that you will be using and what those will represent. For each one of those conceptual requirement types you will be creating an actual requirement type object in your project.
As an example, you could end with requirements like the following:
NEED: Stakeholder Needs
SYS: System Features
SUPPL: Supplementary Requirements
FEAT: Product Features
UC: Use Cases
TC: Test Cases
And you will be creating requirements of each of those types and creating traceability relationships between them.
As you can see, you can easily model your life cycle process inside the project and start creating traceability relationships between the different stages of your process.
Its also quite easy to use.