There is no supported way to do what you want to here - in 2.4.6 the only supported backup and restore mechanism is a full tape backup using BackupExec. However I did write a variation on the full db import/export (which is used today for migrating from 2.x to 3.x) that will allow you to do the import into a 2.4.6 system instead. This is not a TAC supported tool, it's a use-at-your-own-risk kind of thing. That said, a fair number of sites have used it with success. You can find it on AnswerMonkey.net here:
http://www.answermonkey.net/App_full_import_export.htm
It uses the DOH interfaces for the import so it's quite a bit slower than the 3.x import used for migration which uses SQL so make sure you have alotted plenty of time for the import portion. The export is about the same speed as the one used for the migration. Also, be sure to review the "what's backed up and what's not" section in the help file so you know what wont come over (i.e. subscriber passwords).
