The purgeServerSideCache method is deprecated and calling it has no effect - you'll get a console warning about that. This method is now replaced with refreshServerSideStore
[on the client] add a local /etc/[pulse/]default.pa containing:
load-module module-tunnel-sink sink_name=rpi_tunnel server=tcp:192.168.2.13:4713 sink=bcm1
If you don't put a sink_name in, pulseaudio won't start. The sink refers to the sink name on the [server] side [determined via: pactl list | grep -C5 Sink | grep 'Name:']
If you have root access to the server, the easy way to solve such problems is to run sshd in debug mode, by issuing something like /usr/sbin/sshd -d -p 2222 on the server (full path to sshd executable required, which sshd can help) and then connecting from the client with ssh -p 2222 user@host