Handheld App with Certificate

Hi All,
I am using a Handheld HP 6300. A smart device .net application is deployed
on handheld, which uses web service which requires the certificate.
I have installed the certificate on the handheld and now do I do following
1. List down all the certificates present in the pocket pc device (so that
user will choose one of his)
2. User should be in a position to select one of his certificate (and the
same will be submitted with the web service call every time)
3. Now further request to a webservice should carry the selected
certificate along with it, without promting it again

Warm regards,
Shailesh