Mac OS X file association works, but file icon not

I have developed a Mac application using Qt 5.3.2. This application handles files with specific extension (lets say .xyz).

I have created an icon file named XYZ.icns and added it to my app bundle Resource folder (MyApp.app/Contents/Resources/XYZ.icns).

I have also modified the bundle's Info.plist file in order to set the file association. I have added this entry:

<key>CFBundleDocumentTypes</key>
<array>
    <!-- Registered file accociation -->
    <dict>
        <key>CFBundleTypeRole</key>
        <string>Editor</string>
        <key>CFBundleTypeName</key>
        <string>XYZ</string>
        <key>CFBundleTypeExtensions</key>
        <array>
            <string>xyz</string>
        </array>
        <key>CFBundleTypeIconFile</key>
        <string>XYZ</string>
    </dict>
<array>

The result: the file association worked (double clicking on the file does open my application) however, the icon has not been replaced (still displaying the blank document icon).

Is there something that I missed? I looked at other applications for examples and there does not seem to be anything more than what I did.

EDIT: I did some more tests. I dumped the Launch service data with this command:

/System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Versions/Current/Support/lsregister -dump

In the result, I can find claims on file the file type including the icon information:

...

--------------------------------------------------------------------------------
Container mount state: mounted
bundle  id:            105396
    ...
    path:          /Applications/MyApp.app
    name:          MyApp
    ...
    --------------------------------------------------------
    claim   id:            27628
        name:          XYZ
        rank:          Default
        reqCaps:      
        roles:         Editor  
        flags:         relative-icon-path  doc-type  
        icon:          Contents/Resources/XYZ.icns
        bindings:      .xyz
--------------------------------------------------------------------------------
...

EDIT2: After some time, it finally got to work on its own. Overnight, there is an OS update that got installed and I also had to shutdown the computer (the Launch Service probably refreshed something on its own). I would update my question to : How to make sure Launch Service refreshes the associated file icons when an application is installed or modified?

My understanding is certain (built-in) actions trigger Launch Services to refresh the database. Dragging a new .app bundle to an Applications folders is one trigger, as is running a PackageMaker installer. However there may be a disconnect between what's in the Launch Services database and what the Finder shows (until some other refresh/restart).

Some quick Google searching suggests you can force a rebuild from the command line: /System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Support/lsregister -kill -r -domain local -domain system -domain user

However, this step should not be necessary due to the built-in triggers, so I would be hesitant to use it unless you can clearly identify why the built-in triggers fail for your application. And if the problem is the Finder's icon cache, this may not help either.