[cisco-voip] Weird Issue with voice on 2600xm

[chris]

I have a 2600 running 12.4 which has some fxs ports that use sip
registration to register the fxs to a pbx. On this router the WAN is
an ADSL and I've noticed that when the router boots up, when the ATM
interface comes up the voice registration doesnt happen. If I do "no
sip-ua" then repaste the registration config under sip-ua it comes up.

My guess is that at the time the router comes up voice fails to
register because the DSL takes a while to get a sync and for ATM
interface to come up. I would have assumed that IOS would keep
retrying the registration at some kind of interval and that even if it
took a extra minute or two after ATM came up that would be fine but it
seems like IOS never retries because the voice doesnt come up unless I
manually delete and restore the config.

Anyone seen anything like this? Any idea how I can make it all come up
automatically on boot? Its annoying that I have to login after
powerloss and do this manual process to re-establish voice

Thanks
chris