SAP ArchiveLink using a custom object type

[Brian Bennings]

Good afternoon,
 
We are using SAP ArchiveLink to link Accounts Payable invoice images to the
posted SAP documents.  The SAP standard tasks for early and late archiving
(TS30001128 and TS30001117) use methods (IMAGEASSIGNEARLY and IMAGEASSIGNLATE)
within the business object IMAGE.
 
Because our company uses LIV (Logistics Invoice Verification), the A/P Processor
posts an MM/LIV document from the invoice image while SAP generates the
associated FI document from the LIV posting.
 
ArchiveLink links the invoice image to the posted MM/LIV document.  However, we
would like to have it automatically link the image to the MM/LIV document AND
the associated FI document.
 
To do so for late archiving, we copied TS30001117 to a new task and copied the
IMAGEASSIGNLATE to a new method within a Z business object.  We then modified
the ABAP in the new method so that links to both documents would be created.
 
The problem is that when we attempted to link the new task to the archive
document type using transaction SOA0, an error message was displayed indicating
that the task "is not suitable for SAP ArchiveLink" (message number OW 045).
The reason it gave was that the new task "does not have any import parameters
with object type IMAGE."
 
It appears that ArchiveLink does not like the fact that we created a new method
in a Z business object.
 
Does anyone know what we can do to achieve our desired results?
 
Thanks,
Brian Bennings
 
p.s. To those of you who attended the ASUG meeting in Tampa last week... It is
nice to finally put faces to some of the names for those of you who have
contributed to the email group over the past few months.