I proceeded as suggested, "create a co domain". As usual I pointed my domain to my server where I expect to resolve the name. But until now, when the domain is used in internet, it goes to the shared Ip html page. This make me think that my dns configuration needs something else.
Would you help with this ?. something to have in mind is that I´m using a DMZ to reach the server.
I already used dig to confrontate the results of this co domain with another well-working domain. Evertything seems to be good.