[Typo3] tt_products shop and password protected pages

[Harry Jung]

Dear group,

after intensive searching in the groups, i couldn´t find any workaround 
for the following problem:

I have password protected pages (Typo 3.5.0) in which the shop-module 
(1.2.7) is running.

+ Login
   |-> Products-Sysfolder
   	|-> Products-Plugin-Page
   	|-> Basket
   	|-> Cashpoint
    	|-> Tracking

I can login via fe_user, select a product, put it in the basket, see the 
basket, go to the registration page, put in my address data etc.

BUT THEN if i click 'Pay/Order':
-----------------------------------

i get the following error message:

"You have not filled in all required fields with address information. 
Please go back and do that!"


The interesting thing is:
-----------------------------

IF I DISABLE the password-protection everything is going fine and i can 
finalize the order completely.

Is this a bug in the tt_products or TYPO3 Version OR do i have to make 
any other fine-tuning to get this running ??

Any help is very appreciated !

Thanks and best regards,

Harry Jung