The Interface Documentation can only be accessed if appropriate authorizations are available. This includes the authorizations to view and maintain Solution Documentation itself. For further details refer to http://service.sap.com/instguides -> SAP Components -> SAP Solution Manager -> <current release> -> 4 Operation -> Application-Specific Security Guide.
To make full use of the value helps which are available for most attributes it is necessary to have RFC TMW or READ destinations in place to the managed systems which contain the source data.
In order to enable maintenance of custom-specific content your user must have authorization S_TCODE with value AGS_DCM_CUST_IFDOCU. This authorization is assigned to standard roles SAP_SM_SL_ADMIN and SAP_SM_SL_EDIT_BPMN.
If you like to import interface data from an SAP PI / PO Enterprise Service Repository (ESR) via transaction AGS_DCM_EXT_IMPORT you have to provide an additional http destination to the relevant PI / PO system in transaction SM59. This http destination must have the naming convention SOL_DIR_ESR_<SID> with <SID> as the extended system ID of the PI / PO system as maintained in Solution Manager’s LMDB. Provide the Target Host and the Service No. of the system, and enter /rep in the Path Prefix field of the destination. Finally, enter basic authentication data (user and password). The user must have at least authorization SAP_XI_DISPLAY_USER_J2EE to be authorized to call the ESR.