How to downgrade from IOS 7?

I've seen many tutorials for how to downgrade from IOS 7 to IOS 6.1.3 on IPhone 4, but my situation is different. One problem is that the only thing thats shows up on my itunes screen when I connect my phone is a message thats says that i'm not a developer. No 'check for update' or 'restore' options. And my lock / sleep button is damaged and does not work so it can't go in DFU mode.

Go online ands sign up to be a developer it takes 20 seconds

There are many tutorial guide to update iOS 7 without UDID but there are many risk, you can udpate to iOS 7 but can't restore, if you do any wrong step, you still need an UDID, so add UDID is recommend

you need a developer account (99$/year) or request someone have a developer account add UDID for active your device, you can search in Fiverr or fivesquids.co.uk
Something like this:
http://fiverr.com/applereview/activate-your-udid-to-have-ios-7-on-your-iphone-within-5-mitnues