Cisco Firewall :: Unable To Send Mails From ASA 5505

I have 2 subnets bought from my provider 194.102.98.128/27 and 194.102.98.160/27.
 
From my provider a have the following setup:
IP Address:  86.120.151.66
Netmask:     255.255.255.128
Gateway:     86.120.151.1
DNS (1): 213.154.124.1
DNS (2): 193.231.252.1 
My IPs are static routed by my provider thought 86.120.151.66 .
 
On the firewall I have the following set-up:
 
Outside Interface: 86.120.151.66/25 security level 0
DMZ interface: 194.102.98.129/27 security level 50
Inside Interface: 194.102.98.161/27 security level 100
0.0.0.0 0.0.0.0 [1/0] via 86.120.151.1, outside
 
 
Everything works perfectly except when I try to sent an email. The email gets sent (eventually), but afert a long waiting time, 45-60 sec. The connection is opened instally to the server but then just hangs there for 40-50 sec. The problem is that a have an aplication on a server that has to send confirmation emails, and that aplication is limited to a 30 sec timeout for conecting to the mail server, much less then the 45-60 sec that I have now. The mail server is hosted by a data center, it is not in my networks (location).
 
I have tried deleting the ESMTP inspection, that doesn't work. Pinging my mail server rezults in a average time of 20 ms. And when a do a tracert the hight value in a  hop doesn't usually pass 80 ms, the average is 20-25 ms.
 
The problem is ONLY when sending emails. Everything else works perfect, including receiving emails from the same server.
 
My running config is:
 
hostname ASA-Adisys
domain-name Intern.ro
enable password 0./39zRW9yhKK/bO encrypted
passwd 2KFQnbNIdI.2KYOU encrypted
names