Bernie,
Glad to hear that you were able to get at least a partial solution worked out. Having played around with this for the past year or two, here are some tidbits of information that may come in handy.
1) If you are not using authentication when sending/relaying email, then you're much more likely to get your accounts temporarily locked due to 'spam-like' activity. If at all possible, use SSL or TLS-SSL to authenticate against google's SMTP relays.
2) the ASPMX.L.GOOGLE.COM mail relay you've been instructed to use has several limitations that may, or may not, affect you. For example, you'll only be able to send emails to addresses under your domain, or other GMail users. You will not be able to send email through this server to anyone who is not hosted on GMail/GoogleApps.
3) For more info about the restrictions imposed by different methods of sending SMTP email via GMail, take a look at
https://support.google.com/a/answer/176600?hl=en4) If all else fails, and you find yourself with an appliance/app that doesn't support SMTP/IMAP/POP authentication, or won't work with your mailhost, take a look at 'stunnel', a simple network daemon that can function as a relay between an insecure system and a secure host/server.
ie: I've got a TaskAlfa 205c MFP which does not support SSL/TLS-SSL and we had no work-around for utilizing the Scan-to-Email functionality with GMail as the SMTP relay/host.
I configured stunnel on a local box with the valid GMail credentials, and had the MFP send all emails to the stunnel-host without any security/authentication. STunnel accepted the mail from the MFP, and then performed all the authenication with GMail, relaying it for delivery. Everything works wonderfully, until someone ignores the multiple signs on the local box and powers the unit off.