this is nothing new, cisco does it also. THe vpn clinet “captures” the nic and will allow data from your machine to the point of connection. If you try printing to a network printer you will have issues also.
If you dig around in the VPM client settings you may be able to find something like “allow local LAN access” that you can set to true, or “route all traffic through the VPN” which you can set to false. These would allow your computer to still see local network resources, but still use the VPN to get to things that are located on the network to which you are connected via the VPN.
Although SonicWALL is not considered as good as Cisco, the company offers great solutions for considerably less. I am not able to speak for your exact equipment, however, if the routes are configured properly the SonicWALL should be able to route all traffic, through split tunneling or over the VPN tunnel.
In response to the Global VPN Client installation stopping the iSCSI connection to your DroboPro, this is because the installation makes modifications to the Windows network services that requires that service to be restarted. All network traffic is terminated at installation - which includes iSCSI. If the connecting the VPN causes your iSCSI to terminate, this might have to do with no split-tunneling configuration on the client.
Thanks for the explanation… that actually made it all make sense… I think i actually now have more issues related my onboard ethernet not having an updated WIN7 driver… and of course it now likes to only work every other restart…