ZNC now allows one to use the same server for multiple networks. In this case, the password should be login/network:password. Even with one network, this should work, so the password could be unconditionaly formatted like this.
I've created a pull request (https://github.com/sshirokov/ZNC.el/pull/14) with a fix for this issue. I think it might break for ZNC versions older than 1.0, but it may not.
ZNC now allows one to use the same server for multiple networks. In this case, the password should be
login/network:password
. Even with one network, this should work, so the password could be unconditionaly formatted like this.