I've just committed patches to support OpenSolaris to git; thanks for giving me a pointer to a VM image.
There are two things which need to be done. First you need a decent vpnc-script. There are some sample scripts for use with Solaris, but someone ought to send a patch to vpnc to fix the official vpnc-script. Note that you do need to set the MTU on the interface, and openconnect relies on vpnc-script to do that. Also, it only works over TCP at the moment. It needs OpenSSL 0.9.8j or newer to work over UDP -- and you really do want to be operating over UDP if you have any kind of packet loss. -- This message posted from opensolaris.org
