style_name: a unique label associated with the style identifier. This label is the name of the style when Word edit the document.
base_on: the style name used as base style
fp_p: paragraph formatting properties, see fp_par().
fp_t: default text formatting properties. This is used as text formatting properties, see fp_text(). If NULL (default), the paragraph will used the default text formatting properties (defined by the base_on argument).