如何阻止richfaces为面板和日历添加边框？

I'm hoping to use a custom richfaces skin to handle the bulk of my presentation work. Unfortunately richfaces renders borders around every cell in a calendar component and around each panel. I would like to turn them off so that day numbers site in an open grid with no borders. There is no obvious way to do that using skins or attributes of the calendar control. I'm hoping to use a custom richfaces skin to ha