Answer
Add an Enumeration Model directly in Developer Studio instead — an .enumeration file defines a named fixed list with a simple syntax (an enumerationname, a component, and a values block listing each allowed value), which you deploy like any other model file. Then, in the .report file itself, reference that enumeration as the parameter's type (for example, parameter ReportSection Enumeration<YourEnumName> with a default value), and generate/deploy the resulting .rdf as usual. This gives you a genuinely hardcoded, dropdown-driven report parameter without needing to build a custom API method that mimics an existing Enumerate() pattern.