The suggestion to disable the MLSD command is a good one, if only to see if it starts working as expected. I had assumed that SyncBack was using the older LIST command, which apparently it's not. After disabling MLSD, I don't recommend changing the list style to IIS or DOS. By default, it'll use the UNIX style listings I mentioned before (be sure you've got that setting for "treat shortcut as target" set to "yes" 
). At that point, the directory listings you see in the client will look like the ones I posted and not the "Type=OS.unix" style you just posted about (that's the standardized response for MLSD).
The SFTP specification was better thought out in terms of how directory listings are handled and it even includes specific attributes and commands that make working with symbolic links (shortcuts to Serv-U) easier and more straight-forward. Because of this, it doesn't surprise me that SyncBack and Serv-U agree on how to handle the symbolic link when using SFTP.