Hi bisaya,
Well, I am glad someone realizes imported items are too big to go over the net.
I believe you have it backwards. Amazing Utilities will only restore from a .enc file. All the information is there in both, but in order to restore from a pure .bak file (which is basically a backup of a SQL database), you will need to know the syntax to move it to where it needs to go and to change it back to its .mdf and .ldf formats.
The .enc files are the default backup files of your main databases which are made by the backup program. .enc is just the extension for encrypted files. The backup program takes your databases and compresses them first and then encrypts them. You restore them using the restore program, which will look for and find only .enc files.
These are very safe and will quickly restore and overwrite your old databases. You will get a warning about this first. I wouldn't blindly restore without first backing up what you already have and detaching the databases and moving them. But, that is not completely necessary.
If you change the .bak file to a text file (change .bak to .txt) and scroll through the thousands of characters, you will see your data albeit not in an easy to read format.
Also, if you use Amazing Utilities to optimize your database, it will automatically make a new .bak file in your Backup folder inside the AC folder.
I am glad you are backing up both your imported items and your .enc file to a flash drive, but please make sure it is not your only backup. And, you would be better off purchasing two or three large external backups (either USB2.0 or eSATA -- much faster) and backing up your entire computer along with these backups then trusting your entire office and data files to one flash drive.
Hope this helps. Bottom line is don't worry about the .bak files. Just worry about your .enc files.