How to enable tabbing into the list box?

[slingala]

I tried to add tabIndex="0" to the Dual list tag but it did not work.
While tabbing through the elements on the page, when it reached the dual list box, it highlights the whole box than each list item.
I want to be able to tab through each item in the list and enter to move the items into the target list box.
How can I achieve this? Any help would be of great help. Thanks!!