Hi,
I am looking for a solution which checks if the username ist unique 
with the following requirements:
If 
[first letter of first name].[last name]
is not possible as username then
- Try full name: 
 
[first name].[last name]
if not possbile try
- middle name: 
 
[first name].[other given name].[last name]
if not possbile try
- last name only:
 
[last name]
if not possbile try
- add number
 
[first letter of first name].[last name]2
I' am looking forward to a hint.  Thanks