Hi Prem,
1.A If yes, you can copy the message EAN005 / EAN006 to EAN007. There are defined steps which you need to follow which i can explain. Basically you should modify the backend tables if you are using SP3.. If you are on SP4, i guess it is much easier.I am on SP3.
1.B If No, then you can either raise OSS call to SAP and ask them to provide the content for EAN007. Alternatively you can again edit the backend tables.
2.A, If yes,there is no option for you but to create EAN007 message either manually or ask SAP. Once this is done, apply the note 2077700 and B2BToolkit SP03 Patch#15 because while sending custom outbound messages it will fail in the adapter.
2.b If no, it mean customer does not want EAN007 
and you can use EAN005 or EAN006
Thanks
Saurabh