Same here, managed to install it manually, launch Network Connect, authenticate but it fails at some point when establishing the VPN session, before launching ncproxyd. (Using 6.0.0 client, that worked fine with 10.5). btw, ncproxyd runs fine when started manually, but without the right parameters its useless, it needs to be started by Network Connect.app.
Juniper official answer was to upgrade to next IVE OS (6.5 I think) when available, which is not an option for us since it requires upgraded hardware AFAIK.
If anyone manage to make it work with some hacks, let me know. Thanks