How to install self-issued Certificate on Windows Phone 7
For all of you that are using Exchange Server with Self-Issued Certificate, when syncing you Windows Phone 7 with your Exchange Account, you will get the Error Message saying Attention is Required and that Certificate is not Signed.
As we know, there is of course no Settings where you can see or change certificates on your Phone, so the easiest way is to install the Certificate over the Browser. Simply send your self a Certificate per E-Mail and open it over OWA, or just put it somewhere on HTTP for download.
Hold your finger for a few seconds on the Link, then open it on the Window, and you will get a screen asking you if you would like to install this Certificate.
After that you will be able to Sync with our Exchange account :)