RE: Line breaks in labels of new Dynamics AX
If you check the link which you have pasted, it clearly states that labels by standard will not work using line break markers.
You had to use a specific functionality of strFmtLB() in the Global collection class in order to format it like that.
Did you try to use the same function for the label for which you want line breaks in AX7?
If yes and it did not work, maybe you could try to put in <br/> tag instead of \n to maybe try to force it as HTML? I have not tried this way, but may be worth a shot. If AX renders it as text, you might have to check the source of the web page in order to insert the correct sequence of characters to close previous sections and interpret it as an actual line break.