dns srv lookup for TLS when not compiled with TLS

Here's my problem; I'm setting up a connection over a
remote PSTN-GW. This GW sends me a 200 OK and expects
an ACK back.

However, when the openser.cfg reaches the loose_route
part of the config it attempts to do it's t_relay. As
part of that it takes the domain of the gw-server and
looks for srv records in DNS. All well, as it should I
guess - though I would think that SRV lookups were only
done during INVITEs.

HOWEVER! My server is a non-TLS server, and the first
srv record it tries to look for is _sips._tcp... That's
right, secure tls.

The problem is... it finds a srv record for TLS and
says WHEE forgetting that it is not configured (or even
compiled) for TLS operations! Meaning it tries to send
the ACK back to the gateway using TLS... which of
course won't work as the gateway server hasn't set up
any TLS connection with us.

So, the thing to do to fix this is obviously NOT dnsing
for _sips when TLS is not enabled. However, this
requires source modification right? There's not a
parameter or variable I can set somewhere?