How do I set ToolbarSets through PHP?

I want to set ToolbarSets through PHP before

$oFCKeditor->Create();

and tried several options:

$oFCKeditor->ToolbarSets = "My ToolbarSets";//no result
$oFCKeditor->Config['ToolbarSets'] = "My ToolbarSets";//gives error 'menubar Default doesn't exist'
$oFCKConfig->ToolbarSets = "My ToolbarSets";//no result

What is the right way to do this?