boolean File_Passwd_Custom::useMap ( 
    boolean  $bool = null
   )
Whether to use the 'name map' of the extra properties or not.
You first must supply a 'name map' to use it.
$bool
     whether to use the 'name map' or not
Returns boolean TRUE if you set a value, or the actual value if called without param.
This function can not be called statically.