Honestly I don't know what to do with this, but I think the following code does everything you need. Opening the table executes the last line of code.
AddReference "Microsoft.Office.Interop.Excel"
Imports Microsoft.Office.Interop.Excel
Dim oPDoc As PartDocument = TryCast(ThisDoc.Document, PartDocument)
If oPDoc Is Nothing Then Exit Sub
Dim oPDef As PartComponentDefinition = oPDoc.ComponentDefinition
Dim oiPart As iPartFactory
If oPDef.IsiPartFactory Then : oiPart = oPDef.iPartFactory
Else : oiPart = oPDef.CreateFactory
End If
With oiPart.ExcelWorkSheet
.Cells(1, .UsedRange.Columns.Count + 1).Value = "Description [Project]"
With .Parent : .Save() : .Close(False) : End With
End With
With oiPart.FactoryOptions
.PartNumberIndexDigits = 3
.MemberNameType = kPartNumberMemberNameType
.ApplyToAllMembers()
End With
ThisApplication.CommandManager.ControlDefinitions("AppCreateiPartCmd").Execute()