Smart Playlist synchronizing with a folder

Hello all, first would like to thanks all the team for doing such a great work, testing Songbird since 0.1, and the the road done since that one is amazing. OK. Here is my question. Would like to synchronize a smart playlist with a folder wich is not in my library (and i dont want it to be). It's my "download" folder, with all downloaded music from everywhere, it's just a folder to listen and if i like the track, and then only, i add it to my library in Songbird. So i've created a new smart playlist with :
"Place" + "contain" + "file:///d:/Download" (don't know exactly the request in english as i'm using french version). But... it don't works... It's a very important condition for me for switching as i'm using everyday that feature in my actual player aka the incredible Musikcube. Anyone got an idea please ?
Thx