You can use OpenSSL and the Java keytool executable to replace these files with your own certificate files.
keytool -genkey -alias jetty -keyalg RSA -keypass Borland -storepass Borland -keystore keystore -validity 1095
keytool -export -alias jetty -storepass Borland -file server.cer -keystore keystoreThis temporary certificate file is required to generate the certificate files for the machine on which the Silk Test Workbench client is running.
keytool -import -v -trustcacerts -alias jetty -file server.cer -keystore cacerts -keypass Borland -storepass Borland
keytool -importkeystore -srckeystore cacerts -destkeystore cacerts.p12 -srcstoretype JKS -deststoretype PKCS12 -srcstorepass Borland -deststorepass Borland
openssl pkcs12 -in cacerts.p12 -out cacerts.pem -cacerts -nokeys