Maybe [Ontrack Eraser][1] can to do the trick. My dad use it in his work, collecting computers from companies who wants to donate there old computers to Africa. Whey They use the software because the company behind the software provides a certificate that stats that all data have been completely destroyed. They even say that it is better to use this software then to physically destroy the hard drive, because the drive can be reconstructed and analyzed.. But other then that, I don't not nothing about it.
[1]: http://www.krollontrack.com/information-management/data-erasure-solutions/