I tried opening the conversation in conversation view and then I dragged each piece of mail into another email where I could see them, and the mail took a long time to "send", but no attachments were received by the person I tried to forward it to.
It's impossible to select all emails in a conversation, so that won't work.
Seriously, is the only way to forward a complete conversation to somebody is to select and paste the text????
Someone online suggested an app, but that's an ios app, not what I need.