ReadyAPI changes the certificate stored in the keystore when makes new request

Hi 

Im testing a SOAP web service with WS-Security. Im using my public certificate and private key both stored in a pem file

Im importing it as a keystore in to make a request. the problem is that when I see the xml request it turns out that 

ReadyAPI changes the certificate stored in the keystore when makes new request. I would like to know why the certificate added in the xml

differs from the one stored in my pem file.

Thank you