You do not need to be condescending, and it would also help if you read more carefully what I actually wrote. My problem is not with sending text messages (I have already configured MS Outlook to do so), but with replying to messages that already have html formatting. The address book properties do not affect messages to which I am replying. MS Outlook by default uses the same format as the incomingmessage, regardless of what the settings for the outgoing messages are. For example, if compose and send an outghoing message it will be a plain text, because that is how I configured the default. OTOH, if someone sends me an html formatted message and I will reply to it, it will be formatted in html by default, unless I select plain text. By so doing, however, I also lose the line that indicates the original message which is not replaced with ">". MS says it is by design (or so our techsup claims).
The option that you suggested would work only if I was composing original messages to lbo-talk, but not when replying to messages already posted and which happened to have the html format.
Wojtek