Uploading a Developer Certificate for Windows Phone
See
http://msdn.microsoft.com/en-us/library/windows/apps/jj206943%28v=vs.105%29.aspx for information on how to acquire a certificate. You must upload a file in the P12 format which contains a certificate and a private key. Both must match.
To upload a Windows Phone developer certificate
1. Click 
and then Developer Certificates. 2. On the All Certificates page, click 
. 3. Click Browse and select the developer certificate (.p12 file only).
4. Enter the PKCS12 password.
5. Select Windows Phone as the platform.
6. Click Upload.
