Description
The username must start with an alphabetical character and must NOT
contain any other characters than alphanumerics, the underline and dash.
The username MUST NOT contain the custom delimiter!
If you use the 'name map' you should also use these naming in
the supplied extra array, because your values would get mixed up
if they are in the wrong order, which is always true if you
DON'T use the 'name map'!
So be warned and USE the 'name map'!
