Configure Asterisk to be a sip client by 3CX Sipserver

hello,
i have two computers, one with windows and 3CX and the other with linux and Asterisk server. I was able to add the Asterisk server as a voip provider to the 3CX, but not yet the other was round. firstable I created an extension in 3CX(username=callerid=1030. pwd=Phone) and then i tried to add this extension to asterisk in the following way:

register => 1030@192.168.1.253:Phone:1030@192.168.1.253
[1030]
type=peer
context=3CX
secret=Phone
username=1030
;auth=user@realm
host=192.168.1.253
fromuser=1030
fromdomain=192.168.0.254
insecure=very
nat=yes
reinvite=no
canreinvite=no
disallow=all
allow=ulaw
allow=alaw
allow=gsm
allow=ilbc
callerid=“1030”<1030>

where 192.168.1.253 is the IP adress of the windows computer on which 3CX is hosted and 192.168.0.254 is of the linux computer. I was able to log in from the linux computer via SJPhone, but Asterisk did not even try to register (I captured with wireshark on both computers, no packets sent and even in asterisk terminal not shown), what should I change/add? another question: there are many forms for the register command, I mean register => 1030@192.168.1.253:Phone:1030@192.168.1.253, does anybody know what is the specific form for 3CX. In deed there are many forms depending on the sip server, e.g. username:pwd@sipserver[:port] or username@sipserver:pwd:username@proxy ans so on. So what is the standard by 3CX.
here some further information about how it is stored on the asterisk server:

  • Name : 1030
    Secret :
    MD5Secret :
    Context : 3CX
    Subscr.Cont. :
    Language :
    AMA flags : Unknown
    Transfer mode: open
    CallingPres : Presentation Allowed, Not Screened
    FromUser : 1030
    FromDomain : 192.168.0.254
    Callgroup :
    Pickupgroup :
    Mailbox :
    VM Extension : asterisk
    LastMsgsSent : 32767/65535
    Call limit : 0
    Dynamic : No
    Callerid : “1030” <1030>
    MaxCallBR : 384 kbps
    Expire : -1
    Insecure : port,invite
    Nat : Always
    ACL : No
    T38 pt UDPTL : No
    CanReinvite : No
    PromiscRedir : No
    User=Phone : No
    Video Support: No
    Trust RPID : No
    Send RPID : No
    Subscriptions: Yes
    Overlap dial : Yes
    DTMFmode : rfc2833
    LastMsg : 0
    ToHost : 192.168.1.253
    Addr->IP : 192.168.1.253 Port 5060
    Defaddr->IP : 0.0.0.0 Port 0
    Def. Username: 1030
    SIP Options : (none)
    Codecs : 0x40e (gsm|ulaw|alaw|ilbc)
    Codec Order : (ulaw:20,alaw:20,gsm:20,ilbc:30)
    Auto-Framing: No
    Status : Unmonitored
    Useragent :
    Reg. Contact :