BilllingAddress custom metafields are null.

Hi, 
I'm trying create and add new billingaddress with custom meta fields and everything seems to work allright,
but when I reload ICart and get BillingAddress, all meta fields I previously saved are null. 
Any ideas ? 
For example,

payment.BillingAddress.SetMobilePhone(model.ShippingViewModel.BillingContact.MobilePhone);
SetMobilePhone calls out :
   orderAddress.Properties[Constants.Metadata.OrderAddress.MobilePhoneString] = phoneNr;

and after that I call orderRepository.Save(cart)

This only occurs when I need to create new IOrderAddress and add it to the payment the first time.

Using latest Episerver version. 
Regards,
A