[TYPO3-shop] Delivery Adress ignored if "phone" empty

[Uli Linn]

Hi there!

Using tt_products 2.7.1. everything works fine - apart from that:

If every field of the delivery-adress is filled out, everything works as 
expected. If I leave the delivery-phone empty, i get no errer (what's OK 
cause it's not required). But now the complete delivery adress is 
ignored and replaced by the invoice-adress.

How can i force tt_products to either accept incomplete 
delivery-adresses or at least to tell the user, that he has to fill out 
the missing fields? Or, if both is not possible, to take over only the 
empty delivery-fields from the invoice-fields?

Thank you very much for your Help!

Uli Linn