> Why above functions are not implemented on SoftEther VPN 1.0?
>
> In fact, the above features are already implemented. However, they are
> disabled intentionally on the current version. The reason is simple: legal
> problem. We have operated a small company in Japan since 2004. I made
> SoftEther 1.0 in 2003 (the older version, Japanese only). After that,
> Mitsubishi Corporation (a Japanese giant) offered me to make an exclusive
> sales contract of SoftEther 1.0 for 10 years. I was 19. I accepted the
> agreement without consideration, as a person (not company). The agreement
> says that I must not release any freeware which might compete to Mitsubishi
> Corporation's version of SoftEther CA (commercial version for enterprise
> market) until April 2014. So we hesitate to release the function for
> enterprise-use, to avoid legal problem. However, we are trying to convince
> parties concerned so that we will be able to release the extended user
> authentication function on the free version before April 2014.

http://www.softether.org/3-spec/Current_Limitations

SoftEther から PacketiX への商用化路線を強行した件とも関わりあるのかね。