Looking at the most recent macro documentation, those underlined macros are deprecated:
[blockquote]8 These acknowledgement macros are deprecated. Use the more generic $NOTIFICATIONAUTHOR$, $NOTIFICATIONAUTHORNAME$, $NOTIFICATIONAUTHORALIAS$ or $NOTIFICATIONAUTHORCOMMENT$ macros instead.
You may find that (if applicable) on your nagios server’s documentation, under ‘the basics/Standard macros available in Nagios’. I should point out that I’m using 3.0rc2. If you are as well, I reckon you should try using
ACK by: $NOTIFICATIONAUTHOR$\nComment: $NOTIFICATIONAUTHORCOMMENT$\n
instead in both cases. Also, I would point out that in this version the notify command_names are different to those posted by Albin…
Be sure you are changing the actual command you are using.