I have created a self signed certificate like this
#!/bin/bash
EXPIRE=3650
if [ $# -gt 1 ]; then
EXPIRE=$2
fi
mkdir -p $1
cd $1
openssl genrsa 2048 > $1.key
openssl req -new -x509 -nodes -sha1 -days $EXPIRE -key $1.key > $1.cert
openssl x509 -noout -fingerprint -text < $1.cert > $1.info
cat $1.cert $1.key > $1.pem
chmod 400 $1.key $1.pem
And configured my apache vhost to use this cert.
Now I wonder which file I have to import in a clients storage (chrome or firefox) to tell the browser everything is ok!