To send announces with VLC, you need to use the complex syntax of VLC's stream output, like this:

% vlc -vvv video1.xyz --sout '#standard{access=udp,url=239.255.12.42,sap="Test Stream"}' --ttl 12

where video1.xyz is the file you want to stream, 239.255.12.42 is the multicast IP address you want to stream on, Test Stream is the name that will be used for this program in the SAP announces and 12 is the value of the TTL (Time To Live) of the stream and of the SAP announces.