I've been looking at importing data via the Excel Add In and i generally get mixed results. Some table or service imports work as advertised and others do not.
Some of these will work if you consume the service directly from .Net and not through the Excel Add-In.
As an example, we are looking to import potentially thousands of rows into the [ProjHourSalesPrice] table and i have tried importing direct to the table via the Add In and also via a document service. In both cases the insert or update of records does not work but no errors are generated and in the Dynamics status worksheet it claims that no attempt has been made to update records.
Steve. The Microsoft produced add-in only supports 25% of the tables in AX2012. I suggest you give Atlas a go, email firstname.lastname@example.org and request a free trial.
Demo movies are here: Atlas4Dynamics One of these movies shows importing a 10,000 line journal.