Hello everybody,
I am developing a multithreaded windows service in C# whose purpose is to be
a client for a WSE web service with X-509 authentication.

I have to configure a policy file using more than one digital certificate.
In fact, my service must have the possibility to use one certificate per
thread. I know I can configure one <policy> element for each endpoint url,
but I'm looking for a way to use different certificates at the same time.
Here's an extraction of my policy where it sets the cerificates:

<wssp:Integrity wsp:Usage="wsp:Required">
 <wssp:TokenInfo>
   <wssp:SecurityToken>
     <wssp:TokenType>http://schemas.xmlsoap.org/ws/2004/04/security/sc/dk
     </wssp:TokenType>
     <wssp:Claims>
       <wse:Parent>
         <wssp:SecurityToken>
           <wssp:TokenType>
                 http://schemas.xmlsoap.org/ws/2004/04/security/sc/sct
           </wssp:TokenType>
           <wssp:Claims>
             <wse:BaseToken>
               <wssp:SecurityToken>
                 
<wssp:TokenType>http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-x509-token-profile-1.0#X
509v3</wssp:TokenType>
                 <wssp:TokenIssuer>C=it, O=GRTN, OU=CA
GRTN</wssp:TokenIssuer>
                 <wssp:Claims>
                   <wssp:SubjectName
MatchType="wssp:Exact">CLIENT_CERTIFICATO_SUBJECT_NAME</wssp:SubjectName>
                   <wssp:X509Extension OID="2.5.29.14"
MatchType="wssp:Exact">CLIENT_CERTIFICATO_KEY_IDENTIFIER</wssp:X509Extension>
                 </wssp:Claims>
               </wssp:SecurityToken>
             </wse:BaseToken>
             <wse:IssuerToken>
               <wssp:SecurityToken>
                 
<wssp:TokenType>http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-x509-token-profile-1.0#X
509v3</wssp:TokenType>
                 <wssp:TokenIssuer>C=it, O=GRTN, OU=CA
GRTN</wssp:TokenIssuer>
                 <wssp:Claims>
                   <wssp:SubjectName
MatchType="wssp:Exact">SERVER_CERTIFICATO_SUBJECT_NAME</wssp:SubjectName>
                   <wssp:X509Extension OID="2.5.29.14"
MatchType="wssp:Exact">SERVER_CERTIFICATO_KEY_IDENTIFIER</wssp:X509Extension>
                 </wssp:Claims>
               </wssp:SecurityToken>
             </wse:IssuerToken>
           </wssp:Claims>
         </wssp:SecurityToken>
       </wse:Parent>
     </wssp:Claims>
   </wssp:SecurityToken>
 </wssp:TokenInfo>
 <wssp:MessageParts
Dialect="http://schemas.xmlsoap.org/2002/12/wsse#part">wsp:Body()
wsp:Header(wsa:Action) wsp:Header(wsa:FaultTo) wsp:Header(wsa:From)
wsp:Header(wsa:MessageID) wsp:Header(wsa:RelatesTo) wsp:Header(wsa:ReplyTo)
wsp:Header(wsa:To) wse:Timestamp()</wssp:MessageParts>
</wssp:Integrity>

Is it sufficient to add others similar sections to my my policy with
different certificate references? In that case, how can I decide what
certificate to use in runtime without using manual  certificate selection
pop-up dialog ?

Thanks in advance to anybody helping me