Issue: We had a requirement to send in a InventDimId as part of creating a Sales Order, but the InventDimId field was not being populated in AxInventDim table.
Solution : Change the InventDim field property :"AllowEditOnCreate" from No to Yes.
So that system can populate it while its reading the inbound XML.
May be a small thing but thought its worth sharing here.
HappyDaxing...!