I just reviewed again the thread on this forum about this problem and I’ve decided to tackle it in a different manner as there appears to be no resolution to the “custom field in a draft message” problem.

Too bad, as I was trying to avoid having to re-create an e-mail form just to send a reply with some data attached to a custom field.

There was a suggestion to put the data in the body of the message at the bottom, which I might consider, but does not seem as clean.