asterisk and Cisco soundstation IP 7000

Hi,

I got here a Polycom soundstation IP 7000 and all my tests to make it
work with our network fails with the message:

 [Oct  5 06:34:50] NOTICE[2376]: chan_sip.c:15055
handle_request_register: Registration from '<sip:132@...>' failed
for '10.X.X.X' - Username/auth name mismatch

Here's the specific part in the configuration:

[132]
username=132
callerid="hetz room"
;mailbox=132      ; Mailbox(-es) for message waiting indicator
secret=00000
type=friend                    ; Friends place calls and receive calls
context=VIP               ; Context for incoming calls from this user
host=dynamic                   ; This peer register with us
subscribemwi=yes               ; Only send notifications if this phone
vmexten=asterisk              ; dialplan extension to reach mailbox
allowsubscribe=yes
call-limit=99
disallow=all
allow=alaw                     ; dtmfmode=inband only works with ulaw or alaw!
insecure=all

Another configuration which I tested, with fixed IP:

[132]