How can i load a panel page dynamically?

The render process has been broken up into component parts, rather than having them all in one function. As such, there's no clear corollary to the point of entry being exploited in that handbook page. Try panels_page_render_page_norma(), providing it an empty array for the second argument...I guess...and that may work. But no guarantees, that approach isn't one we wrote up or recommend, so we can't support it.