You'll need the ELB toolkit and (optionally) the IAM toolkit
elb-create-lb-listeners my-elb-id --headers --listener "lb-port=8080, instance-port=80"
(You'll need the IAM toolkit for this) If you already have an SSL cert uploaded:
iam-servercertgetattributes -s mysslcertname # This will spit back the ARN string for the cert
I've not uploaded a cert yet with the IAM toolkit but there's a commensurate command there as well
Now add the new listener:
elb-create-lb-listeners non-ssl-elb --headers \
--listener "lb-port=443,instance-port=80,protocol=https,cert-id=arn:aws:iam::9999999999:server-certificate/mysslcertname"