I can't understand why in the External Islands style uses "tdheader" and "alt-1" when the main Left/Right Column style uses "lefttdheader" and "leftalt-1".

Surely that's a mistake?

Obviously, my external sidebar doesn't match the internal one. How can I alter this?

By default, it's set to just use the main tdheader/alt-1 classes. If you want it to match the side column instead, you can just change the class names to lefttdheader and leftalt-1 in the code you get on the External Use link.

OK, so the code I see for the Who's Online is:

so where do I change the class names?

Also, as an example, this code only displays "1 (Username) 43". How do I fill in the gaps and add the extra info to display "1 registered (Username) and 43 anonymous users online"?

Ah, ok. Actually you just need to modify this line:

$style_side="";$tbopen="";$tbclose="";

You'd change that to:

$style_side="left";$tbopen="";$tbclose="";

As for what it's displaying. That's a bug with 7.1. You need to add one more line of code to it. Right before this:

include("/***/***/***/ubbt/languages/english/generic.php");

Add this:

include("/***/***/***/ubbt/languages/english/portal_islands.php");

OK, that works better but I have no border.

Do I need to add the wrapper somewhere here?