Solution
Hi Guys,
On the off chance you haven't already found a solution...here goes!
First of all you need a little app called AnyCut, which unfortunately is not available on the Play Store, and I can't post a link, because I'm new. Sorry. A quick G search will get you the .apk
Install the .apk onto your device. On 4.2.1, at least (my Xoom) trying to run AnyCut from the app drawer does not work. However go to the widgets drawer and select AnyCut from there, and create a shortcut to "Quick Launch". There may be 2 instances of quick launch, if so select the first one.
**I tried for hours to find how to get to quick launch without anycut. Couldn't do it...maybe in the future!***
Now use the widget to access quick launch, and assign your new keyboard shortcuts.
I used it to edit/repair the shortcuts on the top row of my motorola bt keyboard for my xoom. And to change the browser shortcut, to a chrome one.
Hope this helps you!