Overwrite private function

Hi to everybody,
I start to use this week datatables. I found really useful tool for paginating different type of data. Fantastic!

But for make more consistency I try to make a "plugin" for integrate in bootstrap ( Something liked I found around in the blog of Datatables ).

The first customization I try to do; fail when I try to overwrite the function _fnFeatureHtmlFilter.
I want customize this function for get a different html output for the filters.

	/* Change search html */
	$.fn.dataTableExt.oApi._fnFeatureHtmlFilter = function ( oSettings )
	{
		[...]
	};

What I do wrong? Is possible overwrite _fn functions? I look at the code and I find a handler, so need to work theoretically.

Thanks previously for all reply.
Mauro.