Access to a Secure web site with an EPF certificate

[Jean-Christophe]

I'm trying to access from an ASP.Net server to another web site (HTTPS). At
this stage, this site provides a login screen where the users needs to
provide a certificate (filename with EPF extension) and a password.
I would like to passthrough this login automatically from my application.
The certificate is provided by Entrust TruePass.
Unfortunatly, Entrust does not have any API in C# except in Java.
I would like to know if you have already used this kind of certificate or if
you could let me know what shoud I do or test (HttpWebRequest,
CertificatePolicy, ...)
Thanks.