recentlyadded and smartplaylists

I have some Audiobooks in my collection, which i want separated from Music. However using Titan as Skin, I wanted to have the same options as i would have with just Music DB. I made some smartplaylists, However for music Albums, there seems not to be an option to get the list sorted by recently added albums. I came up with the idea to set a path filter, pointing to musicdb://recentlyaddedalbums and adding a Audiobook Genre Filter:

Code:
<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<smartplaylist type="albums">
    <name>Hörspiele zuletzt hinzugefügt</name>
    <match>all</match>
    <rule field="path" operator="contains">
        <value>musicdb://recentlyaddedalbums</value>
    </rule>
    <rule field="genre" operator="is">
        <value>Audiobook</value>
    </rule>
</smartplaylist>

However, this gives just an empty playlist. So i guess path has to be a real path? Is there another way to achive what i try to do? Maybe somehow daisychaining it with output from the library nodes? (Where i tried something similar, which unfortunatelly ignored every parameter i gave after the call to the recentlyadded folder)