Additional Steps for Displaying Documents from Remote Systems 
You need to maintain the document types in the local system as well as in the external system. (Document types are maintained in ArchiveLink Basic Customizing). If you do not maintain the document types in the local system, you cannot display the document type long text in the hit list, and the technical name is displayed instead.
You have to perform the following steps:
Maintain an RFC destination for the external system
Maintain a logical system
Note
The technical names of the RFC destination and the logical system must be identical.
Assign the logical system to an RFC destination.