Managing arrays with NSArrayController

Question

Hi, guys. I'm having trouble when managing arrays that are content of another array. : / I have the plist shown below as an ivar called tools on my Manager class:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"&gt;
<plist version="1.0">
<array>
    <dict>
        <key>Manufacturer</key>
        <string>A</string>
        <key>Image</key>
        <data></data>
        <key>Wired</key>
        <false/>
        <key>NumberMarks</key>
        <integer>4</integer>
        <key>SROM</key>
        <true/>
        <key>Revision</key>
        <array>
            <string>A001</string>
            <string>A002</string>
        </array>
    </dict>
    <dict>
        <key>Manufacturer</key>
        <string>B</string>
        <key>Image</key>
        <data></data>
        <key>Wired</key>
        <false/>
        <key>NumberMarks</key>
        <integer>4</integer>
        <key>SROM</key>
        <true/>
        <key>Revision</key>
        <array>
            <string>A001</string>
            <string>A002</string>
        </array>
    </dict>
    <dict>
        <key>Manufacturer</key>
        <string>C</string>
        <key>Wired</key>
        <false/>
        <key>NumberMarks</key>
        <integer>4</integer>
        <key>SROM</key>
        <true/>
        <key>Revision</key>
        <array>
            <string>A001</string>
            <string>A002</string>
        </array>
    </dict>
</array>
</plist>

On the Interface Builder I'm binding tools ivar to an NSArrayController toolsController pretending to manage its data.This is okay. The Manufacuturer values are the listed in a NSTableView binded to toolsController.arrangedObjects.Manufacturer, while Wired, SROM and NumberMarks are binded to NSTextFields with toolsController.selection.Wired, toolsController.selection.SROM , toolsController.selection.NumberMarks respectively.

This is working great. My problem, as you might suppose by now, is on managing the array Revision inside the other array. I have created on Interface Builder another NSArrayController RevisionController and binded its content to the toolController.selection.Revision.I also have another NSTableView to show its content on the interface binded to RevisionController.arrangedObjects. The content appears with no problems on the interface my issues are: When I try to edit a revsion, the given error appears on the console:

2010-10-15 09:45:43.839 Aimnav Toolbox[10554:a0f] Error setting value for key path  of object A001 (from bound object <NSTableColumn: 0x100231960>  identifier: (null) with object ID 1340 in nib named MNSToolBox.nib): [<NSCFString 0x10012c970> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key .

I have also tried to add new objects in the RevisionController, and the objects added has as values something like this "( )" .

Thanks in advance. Any help is accepted =D