Windows Phone was ported over to the HTC HD2 from the early days proving once again that the HTC Leo was a phone ahead of its time. Once Microsoft outed the Windows Phone 7 Mango Beta, this too was ported to the phone and was working rather well, as we tested it out.
One of the problems with earlier Mango custom ROMs for the HD2 was that the Live services were not working. XDA Developers have cooked a new custom Mango ROM that has a fully working Marketplace allowing you to purchase application just as you would if you’d own a legacy Windows Phone 7 device. Implications (legal, copyright, etc.) aside, you can grab it by following the source link after acknowledging you are doing it at your own risk.
Source: XDA Developers