Yes, you can, but with limitations.
We hope to improve this support in future revisions.
SQLEditor cannot currently auto-detect the driver.
It also doesn't know which dialect to use so it uses the generic one.
The driver is available from the jTDS website
Then decompress if necessary and copy the jar file to the
/Library/Java/Extensions/ directory.
Go to the Database panel of the preferences window.
Add a new database driver by clicking the plus button below the list.
You should see the add driver panel:

Enter these details:
Driver Name: jtds driver
ClassPath: net.sourceforge.jtds.jdbc.Driver
subprotocol: jtds
Then click the Add Driver button.
The new driver should now be available in the Import from database and
Export to Database panels.