If you run into a problem with sending encrypted email via the Motorola Droid Bionic, you are probably running into an issue with Motorola’s replacement for the default mail app: it does not support STARTTLS, only SSL/TLS connections which are encrypted from the beginning. The solution if you own the server is to enable an additional port in master.cf with the smtpd_tls_wrappermode option set.

Or grab K-9 mail.