Internal Customer Invoice Creation

We're still on EBS 11.5.10.2.  We're trying to find a way to allow internal users to create their own invoice type records.  Those records would need to be validated for vendor number, vendor name, account combination, etc.  Workflow would need to route the entries for approval.

At some regular interval the Payables department would import those records that have been approved and turn them into invoices.

We're talking about using all sorts of stuff to do this.  A SharePoint site seems to be the "thing" right now.

We currently use Excel spreadsheets to import from, using the open interface.  But there's no validation and sometimes the wrong vendor gets paid.  (I know, that's why there's an AP Trial Balance Report...)