eDirectory Authentication in .net

Hi, I'm having some issues using S.DS.P LdapConnection to try and 
authenticate a login/password with a server hosting eDirectory.

I've tried this LdapConnection con = new LdapConnection(new 
LdapDirectoryIdentifier(this.SearchRoot), new 
System.Net.NetworkCredential(this.tbUserName.Text, this.tbPassword.Text), 
AuthType.Basic);
where 
SearchRoot = "10.16.173" 
username="customer" 
password="password"
I can successfully log into iManager on the server hosting eDirectory, but

trying in the windows app i get an exception of:
DirectoryOperationException - Confidentiality is required for this
operation

So i tried setting:
con.SessionOptions.SecureSocketLayer = true;
con.SessionOptions.VerifyServerCertificate = new 
VerifyServerCertificateCallback(ServerCallback);

Where ServerCallback just returns true, and now i get an LdapException 
errorcode 81 The LDAP server is unavailable.

Thanks in advance for any advice you can offer, I've been searching for 
quite a while now and keep coming up short.

Adam