frodo rc2 path substutuion help

Hi trying to set up a path substitution for my database folder so that if i have to reinstall xbmc i don't loose the library information.

I have a usb stick that's plugged in that contains my conditional fan art etc so i created a folder called databases and copied my .db files into this, how ever when i start xbmc nothing shows up in my libraries, i have included my advanced settings file below to show what ive done.

Ant ideas?

<advancedsettings>
<useddsfanart>true</useddsfanart>
<cputempcommand>cputemp</cputempcommand>
<gputempcommand>gputemp</gputempcommand>
<samba>
<clienttimeout>30</clienttimeout>
</samba>
<network>
<disableipv6>true</disableipv6>
</network>
<pathsubstitution>
<substitute>
<from>/home/xbmc/.xbmc/userdata/Database</from>
<to>/media/USB KEY/Database/</to>
</substitute>
</pathsubstitution>
</advancedsettings>

Thanks

Matt