Changing the typeface in xml didn't work on the hint text for me either. I found two different solutions, the second of which has better behavior for me:
1) Remove android:password="true" from your xml file and instead, in set it in java:
EditText password = (EditText) findViewById(R.id.password_text);
password.setTransformationMethod(new PasswordTransformationMethod());
With this approach, the hint font looks good but as you're typing in that edit field, you don't see each character in plain text before it turns into a password dot.
2) Leave android:password="true" in your xml. In Java, ALSO set the typeface:
EditText password = (EditText) findViewById(R.id.register_password_text);
password.setTypeface(Typeface.DEFAULT);
This approach gave me the hint font I wanted AND gives me the behavior I want with the password dots.
Hope that helps!