You should look into using RFC enabled Function modules in SAP. There is also an idoc (SAP specific data format file) that is used for standard communication with SAP that would be passed to SAP and then a BAPI called to enter/update information.

There are examples of calling RFC function modules for Visual Basic -- look in the SAP help (http://help.sap.com). You cannot automate SAP -- it is a transaction based system and does not provide this. Your best choice is the idoc with a BAPI call. You will need to talk with your SAP developers to assist with this.