Ribbon Customization: Change to CommandUIHandler does not deploy

Hello,

I am developing a SharePoint-Hosted app to display a ribbon button. When the button is clicked, the CommandUIHandler is supposed to open an aspx page. The initial XML for the CommandUIHandler looked like this: 

<CommandUIHandler 
            Command="Invoke_DocumentSetManageRibbonActionButtonRequest.Command"
            CommandAction="~appWebUrl\App\Ribbon\Pages\MyPage.aspx"
/>

Upon deploying, I receive a server error telling me the URL is invalid. The message is
"Invalid URL: ~appWebUrl\App\Ribbon\Pages\MyPage.aspx"

I went back and changed it to this: 

<CommandUIHandler 
            Command="Invoke_DocumentSetManageRibbonActionButtonRequest.Command"
            CommandAction="~appWebUrl/Ribbon/Pages/MyPage.aspx"
/>

After re-deploying the code, I still receive the initial error message 

"Invalid URL: ~appWebUrl\App\Ribbon\Pages\MyPage.aspx"

For some reason SharePoint does not recognize that I have updated the command XML. I have tried retracting the app, restarting the web applicaiton, deleting and re-adding the feature in my project, and I cannot get SharePoint to recognize that I have changed the command action to point to a different aspx file. 

What is needed to get SharePoint to actually reset the ribbon command so that I can make changes to it, and have it execute the updated XML? 

Thanks.

---

Doug Haining