Specify client certificates in HttpWebRequest in .NET Compact Framework 3.5

Previously, I was trying to use client certificate on .NET CF 2.0 (see here) and I ultimately had to give up. I'm now on .NET CF 3.5 which has support for the ClientCertificates property on the HttpWebRequest object. However, I can't figure out how to instantiate the 开发者_运维知识库X509Certificate or X509Certificate2 object with a pfx file. On the full framework, I can simply do something like new X509Certificate2(filename, password). If I try to create the object with bytes read from a .pfx file, I get an exception saying ".NET CF 3.5 does not support pfx files". So how do I specify a client certificate with a private key for use with the ClientCertificates property?

According to MDSN there are only 2 contructors available/supported by the compact framework:

http://msdn.microsoft.com/en-us/library/system.security.cryptography.x509certificates.x509certificate2.x509certificate2.aspx

The .NET CF supported constructors have a little device icon next to them in the first column.

These are:

X509Certificate2(array<Byte>[]()[])

http://msdn.microsoft.com/en-us/library/ms148413.aspx

X509Certificate2(IntPtr)

http://msdn.microsoft.com/en-us/library/ms148414.aspx