TextTrimming on a splitbutton

Hi,

When a ribbon splitbutton (used as a standalone control) is smaller than the desired size, the text gets cut off and the popup button can only be pressed when the very outer pixels are clicked upon; a click on the arrow itself is seen as a click on the button. How can I make the text use TextTrimming.CharacterEllipsis and thus hopefully make the popup button clickable again?

Thanks,
Robert