Lance, A few years ago, in 2007, there was an auto-spell-check feature in this template. It was removed because it could not match the behavior of the normal mail template. It was too confusing for users. The form-events in this database are different than the regular mailbox template. (Technically this is not a mailbox at all. It's a backdoor to the server's mail.box, which also prevents the normal events from firing in the user interface.)
I will check again the next time I can talk directly with an IBMer. Maybe there is a backdoor to the C-API that I have not discovered.