InDesign CS6 export to EPUB works different from CS5.5 ?

With CS5.5 I have a Paragraph-Style set to place a space of 10 mm before. When I export to EPUB it works fine.

With CS6 the same style doesn't work: any space is left before the paragraph.

With CS5.5 every "Return" (End of paragraph) with blank paragraph (paragraph without characters - only return) is eliminated during exportation to EPUB.

With CS6 also blank paragraph are exported as they are to EPUB.

So, with CS5.5 I had to define particular style in order to obtain spacing between paragraph: How have I to do with CS6 ?

Have I to use only return to create spacing ?

All works done with CS5.5 are so incompatible to CS6 ?

Thanks in advance.

Selene