How to display 0 shipline on Invoice using Report designer?

Hello,

         I need your help. Previously I thought it is easy, but Now I did not find out a solution.

As we know, the 0 shipment line would not turns into ARTran.
So we might meet a situation like 

Shipline                                  ARTran

a                                                     b

b                                                     c

c                                                      d 

                                                         e

line d and e is added by Advanced Direct Invoice Function. So they only have invoice#, no shipment#

line a is shipped 0, so it did not turn into ARtran.

My need is to display on the Printed out Paper invoice with all lines: although a is with 0 qty.

like

a

b

c

d

e

I previously thought is a full join can get this done.

But my problem is, if we are printing Invoice, we normally only know Ref# and Type.

If I apply the Invoice ref# as the where condition,

The line a will still be disappeared,  Because  a.ref is null.
What should I do?

 Can anyone give me some ideas?