How to Create dynamic icon in List UIBB toolbar

Hi I am trying to create a one dynamic icon in list uibb ( without configuring anything from the List Configuration). Is it possible to create a dynamic icon.

I tried with the below options:

1) Created action and assigned to ET_ACTION_DEFINITION for fpm event action.

2) Called a method ADD_BUTTON_ROW and got the button row ref.

3) Called a method ADD_BUTTON_ROW_ELEMENT(Button Type: BT) and passed the above button row ref. in the GET_DEFAULT_CONFIG method.

But button/icon is not getting created.

Is this is correct or should we go ahead with any way to create a icon in list toolbar.