I am trying to manually rewrite the RURI for a certain scenario.

The RURI is currently:
sip:110219546496707@12.12.12.12;npdi;rate=0.000880

I want to re-write so it's just:
sip:110219546496707@12.12.12.12

I have the following snippet which isn't working:
xlog("L_INFO","sip:$(ruri{uri.user})@$(ruri{uri.host})");
$ru = "sip:$(ruri{uri.user})@$(ruri{uri.host})";
t_relay();


the log spits out exactly what I want, but writing the $ru variable results in:
Jan 29 18:59:36 dev-sipgateway /usr/local/sbin/kamailio[23042]: ERROR: <core> [resolve.c:1733]: sip_hostport2su(): ERROR: sip_hostport2su: could not resolve hostname: "$(ruri{uri.host})"
Jan 29 18:59:36 dev-sipgateway /usr/local/sbin/kamailio[23042]: ERROR: tm [ut.h:337]: uri2dst2(): failed to resolve "$(ruri{uri.host})"
Jan 29 18:59:36 dev-sipgateway /usr/local/sbin/kamailio[23042]: ERROR: tm [t_fwd.c:1773]: t_forward_nonack(): ERROR: t_forward_nonack: failure to add branches
Jan 29 18:59:36 dev-sipgateway /usr/local/sbin/kamailio[23042]: ERROR: tm [tm.c:1502]: _w_t_relay_to(): ERROR: w_t_relay_to: t_relay_to failed
Jan 29 18:59:36 dev-sipgateway /usr/local/sbin/kamailio[23042]: ERROR: tm [t_reply.c:1067]: run_failure_handlers(): ERROR: run_failure_handlers: Error in run_top_route

Any hint would be greatly appreciated.