[SYS21] Despatch Interface

We want to interface JBA with a third-party warehousing software. One main
requirement is to send sales orders and distribution order entries (i.e
stockroom-to-stockroom transfers) to the WH s/w and then receive the
despatch quantities into JBA. This second leg seems to be the main
challenge.

What we have succeeded to do right now is to interface the despatch
quantities from sales orders back into JBA. We do this by programmatically
updating files OEP95 and INP57 and calling program OE126CLY which is the
JBA program that does the batch confirmation of despatch (corresponds to
menu options 11/OEP & 14/OER) . This seems to work well (any one can
highlight any issues or pitfalls here?).

Unfortunately transfer order despatches (note: we do transfers by using DRP
option 4/DRP)  cannot be processed by 14/OER, which means that the above
mechanism doesn't work here (or does it? anyone can confirm ?). For
example, if you try  to despatch a distribution order by using the fast
batch despatch 11/OEP, the following message is displayed
"Distribution orders are not supported by fast batch confirmation of
despatch" .

Is there any smart method to achieve this particular interface ?
Of course the hard-way alternative is to update files directly : OEP40,
OEP55, INP57, INP60, INP95 are the ones that come to mind. Has anyone
already done this and willing to share info ?