Mallari,
You CAN use the parameter in the Init. It will require a redesign of your form though. You will need to move the code that is dependent on the parameter out of the Init's of the objects and put it in a custom method, then call that method from the form's Init passing your parameter to it.
Using public variables is a poor design. The requirement for a public variable indicates a flaw in the design of the larger situation and using teh Public var only continues the bad design which will bite you later.