ECM Order Validation

It has been years since I have posted on this list. I will be reviewing
this list from now on so hopefully I could help someone else too. We are
working with a consultant but it doesn't hurt to get a second opinion or
point of view.
The current scenario is that we are on BPCS 4.05CD and planning to convert
to ERP LX 8.3.3. We have a high volume of EDI that we write to XCH/XCL for
PO processing. We do our own validation before and after writing the X
files. Our experience testing ECM on ERP LX 8.3.3 is that it doesn't
handle invalid lines well and also the ability to send 855 PO
acknowledgments up to internal standards. The errors we would need to
validate would be item errors (not found), price mismatches, warehouse
errors, and lead time violations. Item errors would be the one error we
wouldn't want to get through. Well, ship to and customer number also but
that would be abnormal.
Let's say for example we get a PO for 100 lines and 10 of those have
invalid items that need to be set up. In some cases it could be days for
the item to be determined. The way to get these posted would be to have
ECM post the good lines which would leave the 10 lines out there as orphans
without even a PO header. Then when those items are determined, delete the
lines and add them manually to an order. The consultant mentioned this and
it makes sense because that is how standard BPCS does it in 4.05CD (leaves
orphans). That is why we handle item errors our own custom way which
allows reprocessing. Instead of item errors, say they are lead time
violations. We have our own screen in 4.05CD that would allow accepting
those violations and entering the new scheduled date which, by the way, the
new date would be required to be sent on PO ack's (855's) as well. Also,
price errors would allow being accepted. Again, we would need to be able
to send an 855 with "accept with price pending" if we don't agree to the
price. This would need to set the status for posting from ECM even though
the prices don't match. Also, the ability to reject any of those lines and
send the 855 rejection before those post.

Leaving orphan errors and not allowing revalidation is unacceptable in high
volume situations. The manual entry and manipulation would be a huge waste
and ludicrous. We are considering a preprocessor to ECM which would
fulfill our requirements. We have considered writing the TOHB, TOLB, etc
with a certain status to skip ECM for errors. Then set the status when
good or accepted. We have also considered writing the XCH/XCL (X files) or
similar files like in 4.05CD which would be validated and feed the TOHB,
TOLB, etc. Then there are the adapters for customizing validation but I
think I am talking about handling errors in a customized way that wouldn't
require extra manual manipulation. Then being able to accept/reject (also
with possible 855's for certain customers) before the order is posted.

Any suggestions? Am I missing something? Will ECM really do more than
what we think? Has anyone worked around this that could share, please?

Thank you for any input.

Craig Strong