checking actual config DNS+AD

Dear Experts,

Im in the way to check my actual DNS AD configuration, so here same details :

External DNS (mycompany.com)
WAN
Linux Box : (DNS caching mycompany.com)
LAN (intranet side )
Server 1 AD + DNS ( mycompany.local)
Server 2 AD + DNS ( mycompany.local)
Server 3 Exchange 2007
Server 4Linux box running apache

So when I was troubleshooting problem of AD I realize that no mx record in the intranet about server3 was found , so what you suggest to do and how.

Because same dns servers like Server4 are hosting website, I have add to DNS server 1 & 2 records for each name server like:

Toto.mycompany.com =  xxx.xxx.xxx.xxx , and all this zone are declare us  Active Directory integrated primary.

Suggestions in order to re-configure it are welcome

Thanks in advance