how to mangle traffic from router to wan in case i have 2wan

how to mangle traffic from router to wan in case i have 2wan
i know most of ppl wil say its easy to do but try to do it in 2.9
i tried
chain=output src-address=10.5.50.0/24 protocol=tcp dst-port=3128
action=mark-routing new-routing-mark=12345
then i go to ip route as mark it there but nothing happend
i think its from the mangel thing cos i keep watching the counters its not been incressed like what i doing

try taking out the src-address filter and so anything in the output chain gets mangled. Only traffic from router would be in output chain anyhow. what is port 3128 anyhow ?

Sam

i already try it but nothing happend