-Set up a proxy located in US (Google will find you one)
-Set the proxy for all services not only http(ftp,socks.. also), easy done in firefox.
-Use IP lookup to make sure it works. Use Google Maps finding a Hotel near your new IP and use that phone numer code (Numer of hotel incremented by 1 or someting like that)
-Go MS US Support, if it redirects you first to your local site thats because of your browser language not your ip, MS wont care about this, just change language.
-Use Chat (general inquiries)
-Use US Mail (@live.com for example), US Number and fake name if you want
-IMEI .. im not sure, they dont asked mine, can easily found with google for HD7 or try your own, but some stated it wasnt working
Delete all cookies, history etc before! If it doesnt worked the first try, you need to use new Name/Mail or they will see your chat before ;D
Emails sometimes contain a local information, so thats why you dont get a code over email when sent from your local software.
Try a online service, like live.com. Set up the email with us proxy in us language (then you get @live.com instead of @live.de(germany)) and sent your code request from the web-portal