travel from Munich, Germany to Venice, Italy

Rail Europe is a travel agency, not a railroad. Their timetables are incomplete because they only show routes for which they sell tickets. And they don't offer discount fares. The Bahn is Germany's national rail company. They offer bus service on a few routes (like Munich-Prague). If you book tickets ASAP (up to 92 days allowed) on bahn.de, you can get a discount fare as low as €49.00 for direct daytime EC trains from Muenchen Hbf (the main station) to Venezia Santa Lucia (the main station which is on the island). There also is a direct CNL night train. Booking in advance can get you cheap fares in 4- or 6-bunk couchettes and 1-, 2-, or 3-bed sleepers.

There are actually five Eurocity trains (EC) making the day run from Munich to Italy, starting at 7:31, 9:31, 11:31, 13:31 and 15:31. All five terminate in or go through Verona. Only the EC leaving Munich at 11:31 goes all the way to Venice, and for that train you can get an advance purchase Europa-Spezial ticket as low as 39€. If you use any of the others, the Europa-Spezial fare covers just to Verona and you must get off there and take an Italian train (not included in Europa-Spezial ticket) to Venice.

And now that the Trenitalia website is back up (click on the English flag at the top of the page, and Use Italian Spellings for Cities!), I can tell you that you can take one of those trains going to Verona that Lee mentioned, then buy a ticket for the rest of your journey. You have two choices in how you do that: 1) either buy your ticket for Venezia S. Lucia once you arrive in Verona Porto Nuova (7,50€, 2 hours, not frequent; OR (as much as) 23€, 1h11m, much more frequent), or 2) once you're purchased your DB tickets, buy your Trenitalia ticket online for prices as cheap as 9€ for the fast trains. You can purchase tickets about 120 days before travel, so you need to decide quickly if you want the lowest fares. The cheapest price rung can go quickly, depending on the train.