Unfortunately, at the present time there is no way to convert from native .MTF files into SQL Backup's .SQB files.
The only suggestion I can make is to utilise a program such a Winzip ( http://www.winzip.com/index.htm
) or 7-Zip ( http://www.7-zip.org/
), which can compress and encrypt your existing MTF files, but compression and encryption performance may not be as good as with SQL Backup, and it would require additional steps (i.e. uncompressing the archive) when restoring.
I'll add your request to the feature suggestion list for the next version of SQL Backup, and it may be included in a future release of the product.
Hope that helps,