OpenAM change url

I have installed my openam at this addres for example: http://openam-virtualmachine.mydomain.com:8080/openam

I my DNS i have associated openam-virtualmachine.mydomain at this alias: topolino

Now I want to reach my openam using this address: http://topolino:8080/openam but it doesn't works.

There are any solution?

Thanks in advance