Ghatered all styles in "text:style-name" or in "text:class-names" attributes found into the child elements of the span containing the code to evaluate into ERb and moved into a span created to surrond the evaluated code.
At this time seems that text:class-names doesn't work well into Libre Office, so is assumed that only one style is found (putting in into a "text:style-name" attribute").
Emphasized thext font and text size changes.