Sending mail - external MX - problem

[Mono]

Hi!

I have few customers with external MX-es (e.g. googlemail). His MX settings something like:
---------------------------------------------------------------
lola:~# dig MX domain.hu

; <<>> DiG 9.7.3 <<>> MX domain.hu
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 32577
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 2, ADDITIONAL: 2

;; QUESTION SECTION:
;domain.hu. IN MX

;; ANSWER SECTION:
domain.hu. 43200 IN MX 20 aspmx2.googlemail.com.
domain.hu. 43200 IN MX 10 aspmx.l.google.com.

;; AUTHORITY SECTION:
domain.hu. 43200 IN NS ns2.domain.hu.
domain.hu. 43200 IN NS ns1.domain.hu.

;; ADDITIONAL SECTION:
ns1.domain.hu. 43200 IN A xxx.xxx.xxx.xxx
ns2.domain.hu. 43200 IN A yyy.yyy.yyy.yyy

;; Query time: 0 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Wed Aug 31 10:28:25 2011
;; MSG SIZE rcvd: 167
---------------------------------------------------------------
The problem is the following. When I tried send an email to this customer (from webmail or admin message from ispcp gui) the email isn't leave my server.
If the email address is valid on my server, the email goes to the /var/mail/virtual/domain.hu/emailaddress/ folder NOT to the google mail server. This is my problem.
If the email address is not valid on my server, the email bounced with "Unknown user" message (of course this account is created on the googlemail server).

Why not treat the external MX servers the ISPCP? What can I do?

The domain.hu bind file is:
---------------------------------------------------------------
$TTL 12H
$ORIGIN domain.hu.
@ IN SOA ns1.domain.hu. postmaster.domain.hu. (
; dmn [domain.hu] timestamp entry BEGIN.
2011082300 ; Serial
; dmn [domain.hu] timestamp entry END.
8H ; Refresh
30M ; Retry
4W ; Expire
3H ; Minimum TTL
)
IN NS ns1.domain.hu.
IN NS ns2.domain.hu.
IN MX 10 aspmx.l.google.com.
IN MX 20 aspmx2.googlemail.com.

domain.hu. IN A xxx.xxx.xxx.xxx
www IN A xxx.xxx.xxx.xxx
domain.hu. IN TXT "v=spf1 a mx ip4:xxx.xxx.xxx.xxx ~all"
localhost IN A 127.0.0.1
mail IN A xxx.xxx.xxx.xxx
ns1 IN A xxx.xxx.xxx.xxx
ns2 IN A yyy.yyy.yyy.yyy
; CNAME for VHCS compatibility
ns IN CNAME ns1
; CNAME for mail transfer
imap IN CNAME mail
pop IN CNAME mail
pop3 IN CNAME mail
relay IN CNAME mail
smtp IN CNAME mail
; CNAME for web transfer
ftp IN CNAME www
; sub [{SUB_NAME}] entry BEGIN.
; sub [{SUB_NAME}] entry END.
---------------------------------------------------------------

Sorry for my English.