I need to sign an applet with Avaya trusted certificate, I managed to get certificate file from Security->Certificate Management->CA Trusted Certificates .
i used the avayaprca jks file to sign jar by following below steps

1- import certificate
keytool -import -trustcacerts -alias avaya2 -file "D:\AESClient\AES138.crt" -keystore "D:\AESClient\avayaprca.jks"

2- sign jar
jarsigner -keystore "D:\AESClient\avayaprca.jks" -storepass password -keypass password "D:\AESClient\ctiavaya.jar" avaya2

I get below error,
jarsigner: Certificate chain not found for: avaya2. avaya2 must reference a valid KeyStore key entry containing a private key and corresponding public key certificate chain.

Only Avaya can use the Avaya CA certificate to sign anything. The cert installed on AE Services contains the public key but not the private key which would be needed for signing.

To the best of my knowledge, if you need to sign your applet, you will need to do one of the following:

1. Use a commercial signing service (e.g. Verisign)
2. Setup your own, private, Certificate Authority (basically a Self-Signed cert) and use that to sign your applet. You may then need to install your CA cert in all the browsers on which your applet will run.

Martin