Oh, if you already have the button you want in your config and you want to send it to someone else, just to the following:
On your computer:
[ul][li]Select Settings -> Customize Toolbars to put Opus into toolbar editing mode.[/li]
[li]Drag the button that you want to a folder, which will create a .dcf file of the button.[/li]
[li]Click OK in the Customize window to put Opus back into normal mode.[/li][/ul]
Send the .dcf file to the other computer. Then, on there:
[ul][li]Select Settings -> Customize Toolbars[/li]
[li]Drag the .dcf file to the toolbar.[/li]
[li]Click OK in the customize window.[/li][/ul]
Alternatively, if it's easier to send text than a file: While in Customize mode, right-click the button and choose Copy, which converts it into text in the clipboard. Paste that text into an email and send it to your brother. He can then put his Opus into Customize mode and paste that text on to his toolbar to re-create the button (explained here in more detail).