Hi David,
No, it's a lot easier than that. Go to the message you found. Left-click on the mouse and hold down at the beginning of the message, then drag the cursor to the bottom of the message (still holding the left-click down). This will highlight the whole message. Release left-click. Then, while holding the cursor over the highlighted part, right-click. This gives you a drop-down menu. Right-click on "Copy".
Then go to "Post new" on the Live Forum and open a new message screen. Right-click, and see the drop-down menu - choose "Paste".
It's actually easy to do but hard to explain! Let me know if it doesn't work.
Sue