SAP Mobile Server communicates differently with replication, messaging, or Gateway applications.
However, in non-Afaria environments or for non-ODATA applications excluding those for BlackBerry, SAP requires that you initially install the messaging application, and connect directly to the messaging service on the corporate LAN (via Wi-Fi, cradle, and so on). Once initial registration is complete, the device can be used outside of the LAN by substituting the connection profile properties to use the Internet-accessible (typically, Relay Server) addresses. See Provisioning Security Artifacts
For BlackBerry devices, because the BES is already inside the LAN, the initial provisioning of the RSA public key is considered safe.