Don't quote me on it be I don't think it will be too long now, since other 1520s have been receiving the update (UK, Hungary, Taiwan, Finland and maybe a couple of others). If on the screen you were asked to look at, it says Country Variant or CV then your phone isn't locked to a specific carrier. With unlocked phones it doesn't matter what SIM is in the phone, as the update system goes off that the phone's ROM is, in your case the Italian Country Variant.
I'm guessing by DP you are running the developer preview - due to an issue regarding the Cyan update and phones with a certain configuration running the preview, Cyan updates have been paused for all devices running the preview until MS can sort a fix out - and they say that if you want the update earlier then you need to use the nokia recovery tool (have a hunt around there's a thread for it somewhere). Otherwise I would recommend sitting tight - they might release the fix around the same time Cyan is released in Italy.
Here's the link if you don't have it already, for Nokia's update tracking page:
Availability in Europe - Nokia