Without having your rtf to test with I still have no idea what you're actually seeing. Unless you look in the html there isn't really any way to tell whether the spaces you're referring to are actually in the html or in the css styling. Itimpi and myself have asked you to check the html several times now to no avail.
I've attached an rtf file that converts fine on my system. It's the test file I used when investigating your original report about soft breaks being deleted.
This rtf converts to epub with spacing between paragraphs - but not blank lines - that's Calbre's default style. If you want to get rid of them add the following line to extra css under look and feel - note I've already explained this to you:
Code:
p {margin-top: 0em; margin-bottom: 0.3em}