Sozialversicherungsausweis and Italian INPS (Hamburg)

Hello,

I'm planning to move to Hamburg next December. I've read that one of the documents you're expected to submit to your prospective employer is the social security card; acording to the Deutsche Rentenversicherung website, as an EU citizen, I'm strongly advised to apply for an equivalent document in my home country. In Italy we have several authorities dealing with social security; anyway, in my case it would most probably be the INPS.
As far as I'm informed, though, in Italy it is normally the employer who takes care of social securuty issues; there are some possible exeptions, none of which appears to fit my case, as presently I'm not employed. As far as social security is concerned, I practically do not exist.
Thank you for any advice.

P.S. : I'm quite fluent in German.