how the Person.Dialoguserpassword be initialized

From the 1IM Operational Guide, it tells 

Using a password policy

You can assign password policies to system user passwords, the employees' central password as well as passwords for individual target systems. Assign a password policy to the base object to which it should apply.

  • The predefined One Identity Manager Password policy password policy is assigned to the (DialogUser.Password and Person.DialogUserPassword) system user passwords as well as the passcode of the employee (Person.Passcode).
  • The predefined password policy Employee central password policy is assigned to the employee's central password (Person.CentralPassword).
  • The password policies for target systems are assigned to the password columns of the user accounts.

I set initial password on the both predefined password policy like 'P@ssw0rd'. When I create an Employee usring Manager and don't key-in anything on the relative password field. 

After save, 1IM can sync centralpassword to other target system, but when I login on password reset web or other web portal, I can't logon using the dialoguserpassword

I don't know why the dialoguserpassword not be initialized, I have set an initial password on the password policy. 

Please help , if you have any suggestion or tell me "You have wrong concept",

Very Thanks~~