Google Appengine not signing emails with DKIM code
How long ago did you create your DNS TXT record?  Since DKIM is a DNS controlled service, and DNS often takes up to days to propagate across the Internet, you may need to wait for that to happen before Google will recognize it as valid.
Am confused why emails sent by my appengine app are not being signed with DKIM.

Enabled DKIM signing on Google Apps dashboard.  Confirmed that my domain is "Authenticating email"
Have setup DNS TXT record using the values indicated in the apps domain.  Have confirmed, using 3rd party validation tool, that the DNS is correct.  Also, I assume that having a green-light indicator for authenticating email in my Google Apps domain means this record has been validated by Google Apps.
Email-send is being triggered by a click by a user browsing my application via my custom url.  The custom url matches the domain for the return address of the sender. The sender return address is an owner of the account.

As far as I know, these are the requirements for emails to be signed automatically.  Yet, alas, they are not being signed.  Any help or ideas will be greatly appreciated.  Thanks -