[mad-max]

You need to edit the IncludesHomeMenuItems.xml...

There in you have the sub for movies:

Code:

<include name="HomeSubMenuMovies">

then you have to create a button for the entry:

Code:

<control type="button" id="90167">
    <include>ButtonHomeSubCommonValues</include>
    <label>Name of your button here</label>
    <onclick>XBMC.ActivateWindow(10025,special://skin/playlists/Playlist.xsp,return)</onclick>
</control>

This requires that the playlist is in the skin folder "playlists"...
But you also can change the path to whatever you like...

cheers,
mad-max