I have 3 network connections.... one is wireless, one is a standard ethernet port that connects to another device, and the other one is a standard ethernet port that connects to the dreambox.
Strangely, I dont have to disable anything. I can FTP, stream, webinterface etc without having to change connection settings. The dreambox is set to 192.168.0.24, and the ethernet adapter that connects to it has been assigned an IP of 192.168.0.2. My wireless network is on DHCP and maintains an IP of 192.168.0.4, and my other ethernet connection has an IP of 192.168.1.2. All work fine. I dont use the same nameserver/gateway IP address on any of the connections.