Both of these options should work.
As you say, in the first option, you do have to change the IP address at the dnsitalia DNS server whenever Dreamhost reassigns the IP address of your apache server. This does not really happen that often, and there are tools/scripts you can use to notify you when it happens so you can edit your entries.
The second option seems like it should work. You'd definitely need to wait a long time for DNS to propagate and you really need to make sure with your domain registrar that you're doing it right at their end.
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