short dump when implementing CL_DD_BUTTON_ELEMENT

I have found a Class/method to disable or make invisible a button on a screen... yay! :lol:

anyway, this is what i have coded so far in my BAdi....

      DATA: lc_dd_button_element TYPE REF TO cl_dd_button_element.
      DATA: lc_dd_form_element   TYPE REF TO cl_dd_form_element.

      CREATE OBJECT lc_dd_form_element
        EXPORTING
          id = 'A1F1B5'.

      CREATE OBJECT lc_dd_button_element
        EXPORTING
          id = 'A1F1B5'.

      CALL METHOD lc_dd_button_element->disable_button.

the 'ID' is the button i am trying to disable...

can someone point me in the right direction? when i debug this, the id has a value, so i added the object lc_dd_form_element but it still short dumps...

the short dump is: Runtime Errors OBJECTS_OBJREF_NOT_ASSIGNED