Workaround:
Put a <tab> before the line-break

You can search for a "justified formatted line-break" using the "Find and Replace" dialog:
Search for "\n" (without the quotes), check "[x] regular expression" and klick the "Format"
button. There you can choose "justified" on the tab-page "Alignment". Don't forget to 
check "[x] including styles" in the find dialog.