Yes, it is possible to specify the 'From' parameter in the subject when using the "Known Email Sender" feature.
You are also about to set the default Sender's Id in your account Preference -> Option page.
Great, thanks (in that case please change the feature request to updating the manual to make this clear :-)
Yes, knew about the Preference Option etc, and have that set the way we usually want it, but occasionally want to override that.
Cheers