Sip peer problem

Hi, i used (in version 1.0) to declare my peers this way

register => @softswitch-in

[softswitch-in]
type=friend
host=192.168.10.102
context = from-external
dtmfmode=rfc2833
insecure=very ; required for incoming FWD calls

I upgraded to 1.2.4 and now i got error about the format of registration:

Feb 28 16:49:34 WARNING[11142]: chan_sip.c:3207 sip_register: Format for registration is user[:secret[]]@host[:port][/contact] at line 154

This is a cisco 5400, and i dont have defined any user, only the peer,

how can i omit the username in sip.conf?

thanks