It should be possible using MFormCustomDraw class.
From SDK help:
virtual void DrawLineGraphics(const TParam& aParam,const TLineInfo& aLineInfo) const;
This function is called after the background has been drawn by DrawBackground(), and before drawing the text. This function might be used to draw a ruled line under each line of text.
The default implementation of this function does nothing.
But to be honest, I've never been able to make it work..:-(
If someone has working example, it will be highly appreciated.