Connection to a web site with SSL setting: Require ClientCertificates is not supported in the current Windows Phone 7 application model. (note: only BasicAuthentication is supported).
As you noted, ServicePointManager is not exposed to Windows Phone 7 applications and there is no other method available to applications which would allow you to intercept the server certificate validation.
(http://social.msdn.microsoft.com/Forums/en-US/windowsphone7series/thread/6d6c8adf-016b-421c-bd1e-ff717f01903c)
Блин, может есть костыль какой?
