How do I use class helpers to access strict private members of a class?

Question

This is a follow-up question to: How to hide a protected procedure of an object?
(I'm a bit fuzzy on the whole class helper concept)

Suppose I have an class like:

type 
TShy = class(TObject) 
strict private
  procedure TopSecret;
private
  procedure DirtyLaundry;  
protected 
  procedure ResistantToChange;
end; 

I know I can access the private method if I have the source code by adding a descendent class in the same unit.

I have 2 questions:
- How do I employ a class helper to access the strict private member?
- Can I use a class helper in a separate unit to access (strict) private members?