The "Missing-Link-Server" ( MLS ) provides the core services to communicate with SAP-Systems interchanging IDOC-Messages. The service is implemented for transaction processing environments enabling you to change data in the SAP-System in secure manner supporting SAP- ALE monitoring functions.
The MLS enables your NON-SAP-Applications to communicate online with SAP-Systems providing the SAP-ALE service. The MLS hooks on a ODBC- database reading/writing the messages there. Your system uses only the local database services via ODBC or any other database interface language your DB supports.
A new feature to be implemented will MLS allow to send/receive mails supporting the concept of implementing small companies in your automatized SAP processes.
The products 
MASTERDATA-Server , INVOICE-SIGN-Server and DOCUMENT-SIGN-Server based on MLS.
e.g. MLS supporting signature services for Invoices:
