You can do it one of two ways; write CODE then paste your autoscan and write /CODE - obviously both CODE statements need to be in [square brackets]
- or -
If you have 'Gone Advanced' you can highlight the text you want and then click the 'pound' or 'hash' symbol # and that will wrap your post in the code tags. If you use the Go Advanced function, you may also preview you post before submitting. This will show how your post looks beforehand.