Below is an HTML code, exported via SaveHTMLToStreamEx:
<p style=" text-align: left; text-indent: 0px; padding: 0px 0px 0px 0px; margin: 0px 0px 0px 0px;"><span style=" font-size: 10pt; font-family: 'Arial'; font-style: normal; font-weight: normal; color: #000000; background-color: #ff0000; text-decoration: none;">Some text</span></p>
The problem is that RvHtmlImporter silently ignores 'background-color' style.
One more issue: SaveHTMLToStream (without 'Ex') does not even export this style!
Any ideas?