QF subforms: separate form template for the subform?

I am experimenting with the *splendid* QF "subform" element. So far so good. Now I want to assign a distinct form template to the subform, distinct from the main form's template, that is. I really mean here the form template, not the element template for the subform element (this can be set as usual, which is great) Has anybody an idea whether this can be done? At first sight it can not: it seems to me that there can be only one renderer instance, which can be assigned only one form template. Hopefully I have overlooked something... I am using HTML_QuickForm_Renderer_Default() Thanks