How to redirect port on LAN interface for transparent siproxd?

[Master One]

I am playing around with setting up asterisk (specifally askozia, which is an embedded solution based on m0n0wall similar to pfSense) behind pfSense without success so far. I want to use siproxd as a transparent proxy for that purpose, as described here.

That setup should be pretty straight forward, and there is little to do. The major problem is, that I just don't get it, how to redirect outbound traffic on port 5060 through siproxd, like it is outlined for iptables:

redirect outgoing SIP traffic to siproxd (myself)

iptables -t nat -A PREROUTING -m udp -p udp -i eth0 –destination-port 5060 -j REDIRECT

I tried setting up a NAT Port Forward like this:

Interface: LAN
External address: any
Protocol: UDP
External port range: 5060
NAT IP: 192.168.1.1 (that's the pfSense LAN IP)
Local port: 5060

but it just does not work.

Any hint?

[Master One]

I think I know now, how to solve this issue, but I still don't know how. Please have a look at my posting in the SIPROXD Transparent Proxy thread.