Sorry for the delay only got back today.
No unfortunately we never sorted this out. The problem appeared to be related to the fact that we were using the extension sch0. According to Baan the inbound EDI message is only supported from sch1 upwards.
We are still discussing this along the grounds that the Maintain Receipts session in sch0 asks the user whether they want to use an ASN but the EDI session doesn't work and puts it into series 0.
Just as a matter of interest are you using an extension ?