Issues with xbuilder.insertStyleSeparator()

I’m trying to make a paragraph where two styles coexist. For this I have found a tip that tells us to use the insert, however I can’t get it to work. I have downloaded the tests from Github and I see that the specific test for this section has not been able to work either (Asposeword-for-java-master). How can I apply two styles within a paragraph - one style for one part of the text and the other style for the rest?

for (ResponseEntity r:q.getResponseEntities()) {
    builder.getParagraphFormat().setStyle(styleResponse);
    builder.getListFormat().setList(listResponse);
    builder.write(r.getTxt());
    builder.getListFormat().removeNumbers();
    builder.insertStyleSeparator();
    builder.getParagraphFormat().setStyle(styleIdx);
    builder.writeln(" ["+r.getId().toString()+"]");
}

@AGARCIA.GIJON As I can see style separator works fine. I have used the following simple code for testing:

Document doc = new Document();
DocumentBuilder builder = new DocumentBuilder(doc);

builder.getParagraphFormat().setStyleIdentifier(StyleIdentifier.HEADING_1);
builder.write("Heading 1 Style");
builder.insertStyleSeparator();
builder.getParagraphFormat().setStyleIdentifier(StyleIdentifier.HEADING_3);
builder.write("Heading 3 Style");

doc.save("C:\\Temp\\out.docx");

Thank you very much for the example. I have tried it and it actually works as expected.
The mistake has been mine since it was to test. The result is that I opened the document on my Mac with Pages and the display does not correspond to what the document shows when it is opened in Word. Even the preview that Gmail offers shows line breaks in the style changes of the same paragraph (without these line breaks existing in the document).

@AGARCIA.GIJON Actually style break is a paragraph break with special properties.

<w:p w:rsidR="00A77B3E">
	<w:pPr>
		<w:pStyle w:val="Heading1" />
		<w:rPr>
			<w:vanish />
			<w:specVanish />
		</w:rPr>
	</w:pPr>
	<w:r>
		<w:t>Heading 1 Style</w:t>
	</w:r>
</w:p>
<w:p>
	<w:pPr>
		<w:pStyle w:val="Heading3" />
	</w:pPr>
	<w:r>
		<w:t xml:space="preserve"> </w:t>
	</w:r>
	<w:r>
		<w:t>Heading 3 Style</w:t>
	</w:r>
</w:p>

Most likely Pages and Google Docs do not support <w:vanish /><w:specVanish /> attributes of paragraphs.