how to insert conditional line break in lyx?

[Mikko Rantalainen]

I have a very long url which I need to insert into my text, but lyx/latex
seems not to be able to break it. How do I tell in lyx that it can break
line *without* hyphenation mark between some characters. I know normally I
should use <control>+<minus>, but it inserts hyphenation mark.