SWEC : Change Document Events, Passing Old/New Values to Workflow Container

[Workflow]

Hello fellow workflowers

System : 4.7

Problem : Passing the new/old values (index 0001 and 0002)from the event
container to the workflow container

SWEC has been configured for BUS1006 (Business Partner) change on field
BUT0BK-BANKN (Bank Account).  A custom event ZBankAccountChanged has been
add to ZBUS1006 via delegation with event-parameters to capture
CD_OBJECTCLAS, CD_OBJECTID, CD_CHANGENR from the event container and
transfer them via normal event-workflow binding.  A multi-line event
parameter "BankAccount" has been configured exactly as recommended in "the
book" on page 300. I set up in ZBUS1006 "a database attribute (BankAccount)
... making sure that the ABAP Data Dictionary reference of the attribute is
identical to that of the field in the change document".  So far so good,  my
event is triggered and I see in the event container a multi-line parameter
"BankAccount" with two entries containing the new and old values
respectively.

Now the problem, the transfer of this multi-line parameter to the workflow
container is hung up.
I have created in the workflow-container a multi-line parameter of the same
name "BankAccount" and bound it to it's peer in the event container.  No
transfer.  I have tried binding via "assign" and "append" and no transfer
takes place.

Has anyone else encounterd this.

many thanks
Nate