Remote debug with xdebug

Hi,

I'm on PhpStorm 2.1.5.

I usually debug with xdebug and PhpStorm on local projects, and it works fine. I use the xdebug helper under chrome.

Now I'm working on a remote project, which I opened with "Open directory" on a mounted drive.
Debug is not working (doesn't detect incoming connection, doesn't stop on breakpoints), but I don't know why. I tried to follow the video about remote debug, but it's quite old and I can't see option "debug -> remote" as it says.

May be I have to open this project as "New project from existing files -> remote server", but I try to avoid this as I don't want to download the whole project, it's huge.

Thanks for your help.
Lo