oh that is easy.... Just make sure you are not signed into vudu. enter the code in sony. when it asks where you have bought it then say walmart. It will prompt you to be transfered to vudu. Vudu will tell you the movie. Just click out of it.... Do not press continue. And the code will still be useable :)
@Katomine, you cant test codes from sony, once it switches from sony to vudu the code is often times killed... you may have ruined the code. You can do this on vudu or flixster with most movies. but for sony codes you need to look up the first 3 numbers to the code to see what they are. they only have 1-4 different per movie per format.