That's a limitation of SAM.
SAM's encoders are built so that they only update the track info if the currently playing track changes. The metadata of a stream is unavailable until it actually finished connecting, though. Therefore SAM can't forward the meta info from internet streams out of the box.
You can manually enforce a title change on the encoders using PAL and there are a few readymade scripts for parsing Shoutcast to be found on this forum.
This one from 2006 is for Shoutcast v1, I have no idea at all if Shoutcast v2 still has the 7.xml stats interface: viewtopic.php?f=20&t=52357
IIRC Icecast has a compatible statistics output that follows the same format as Shoutcast's 7.xml or 7.html ones. One might need to manually enable these, though, depending on the distribution.