Multiple Invoice type to single Invoice list

Hi,

I am getting data for various interfaces and based on which i have defined order types and billing types respectively. However while trying to create invoice list from these invoices standard SAP R/3 throws a error. I am using IS-Utility for billing and process followed is Order to Invoice hence there is no delivery

Eg:

Interface                                   Sales Order type                         Billing Document Type                         Invoice List Type

  Test1     ------->                                  Z001          ------->                             Z001                     ------->                         Z004

  Test2     ------->                                  Z002          ------->                             Z002                    ------->                          Z004

  Test3     ------->                                  Z003          ------->                             Z003                    ------->                          Z004

Message for Error log:      "The billing type could not be determined for the specified transaction"

Can some Please help me and give me viable fix for the same.

Thanks In advance,

Anand Iyer