Hi,
instead of a default text box control you can try to use:
<cms:CMSHtmlEditor ID="editor" runat="server" />Of course you will need to modify the code behind to cooperate with this new control.
It would be better if you created a
clone of message board web part and related controls. Then you changes will not be lost in case you apply the hotfix.
Best regards,
Ivana Tomanickova