Hi robbi3j,
Could you post the configuration file you're using here, as well as any error messages from your attempts to get stunnel working with this cert?
Stunnel doesn't actually care whether a given cert you're handing it is wildcard or not, so that shouldn't make a difference in this case. Also, if you intend the stunnel process to be started in some automated way (eg. on machine boot), I highly recommend not having the key encrypted in the .pem file. You should be able to strip the encryption off the key using the openssl command line utility, eh. (Obviously, don't post the key here if you do that, eh!)
Thanks,
Stephen