Replacing tray/dock icons without a launcher

[Preev]

I was tooling around forums today and found a few people asking how to replace the stock icons with icons for other programs (calculator, camera, calendar and so on). To do so on the Epic 4G touch:
Applications--->
Menu botton (far left bottom button on phone)--->
Change to "View Type"--->
Choose "Customizable Grid"-->
Menu botton--->
"Edit"--->
then drag and drop icons from your list

Be sure to save click the menu button when you're done to "save" your changes.

 

[jackbq]

Hi,
I am using a Galaxy S3 and deleted the internet icon from the tray at the bottom of the home screen. I wanted to replace it with Opera, but for some reason I cannot add opera or even the old internet icon back to the tray.
I tried the above (I know it is for the Epic) and while I can add icons to the main screens, I cannot add anything to the tray. Can anyone help?

At the moment I have phone, address book, messages, blank (where internet was), apps.

Thanks.