Synonyms have been around since 2005 for SQL Server. Per support, synonyms are not available in Spotfire Analyst due to "issue/lack of feature" in the MSSQL JDBC driver. You can find many posts on this issue online, a couple of them are these:
http://tech.forums.softwareag.com/techjforum/posts/list/51393.page
There is an enhancement request active to see if it is possible for Spotfire to work around this limitation in the JDBC driver.
Please vote for this idea to turn it into a feature.
The only problem is that synonym is not shown under data source's tree in Information Designer, one can workaround this by creating information model from the table that the synonym is referencing, then manually edit the information link's SQL to select data from the synonym.
One of our customers also wants to utilize synonyms in MS SQL Server.
Please implement this.