I found the solution. Maybe it will interesting to anybody:
%<\AcDiesel $(nth, 0, "Expressed value", "Description", "CompanySite", "AssemblyName", "ClassName", "MethodName", "ParameterValue")>%
With this info I can:
- Get the assembly.
- Get the Class for the value expressing.
- Get the Method for the value expressing.
- Get the Argument for the value expressing.
- Get the developer's site.
- Write the expressed value as a String value.
The Reflection can help me. For example, I can use it for getting (programmatically) the Subset custom property's value in the SheeSet and display the result as a Field in the some text.