now i know better the details of the procedure 

- everybody uses a neutral language which is vcard language
but each tools (contact , kaddressbook ) uses its own language to create a view

- contact editor knows "TEL;TYPE=FAX" and displays "Autre fax"
but contact does not know how to display "TEL;TYPE=FAX" !

- kaddressbook knows  how to display "TEL;TYPE=FAX;TYPE=WORK"
but kaddressbook does not offers to create an object "TEL;TYPE=FAX;TYPE=WORK" !

- syncevolution is neutral when communicating with others

my conclusion :

- syncevolution has no pb

- contact has a pb : it does no know what is "TEL;TYPE=FAX"

- kaddressbook editor has a pb : it does not offers to create a
"TEL;TYPE=FAX;TYPE=WORK" or "TEL;TYPE=FAX;TYPE=HOME"