Infelizmente, isso não parece ser possível.
Abaixo estão algumas fontes para esta informação.
Wikipedia: Secure Socket Tunneling Protocol
SSTP is only available in Windows since version Windows Vista SP1, and in RouterOS. It is fully integrated with the RRAS architecture in these operating systems, allowing its use with Winlogon or smart card authentication, remote access policies and the Windows VPN client.
Problemas de PPTP / L2TP e soluções SSL
SSTP is a great addition to the VPN toolkit to enable users to remotely and securely connect to the corporate network. But there is no solution for Linux, MAC OS and other OS, SSTP limited only for Windows users and seems it's a big problem.
As próximas duas fontes são de provedores privados de VPN.
If you use a computer that installed Windows Vista or Windows 7, Congratulates you! you can use SSTP vpn on your computer. It's unfortunate that other operating system do not support SSTP vpn current.
SSTP Configuration instructions can be found here: SSTP VPN Configuration for Windows 7