Note: Due to changes made to jQuery 1.9 and jQuery UI, this answer is no longer the correct one. Please see @stankovski's answer below.
You need to find the tab's index first (which is just its position in a list) and then specifically select the tab using jQuery UI's provided select event (tabs->select).
var index = $('#tabs ul').index($('#tabId'));
$('#tabs ul').tabs('select', index);
Update: BTW - I do realize that this is (ultimately) still selecting by index. But, it doesn't require that you know the specific position of the tabs (particularly when they are dynamically generated as asked in the question).