How to create rich tooltips and rich balloons in notification area

You have to use the Win32 Function Shell_NotifyIcon. You can set the dwInfoFlags member of the NOTIFYICONDATA structure to NIIF_USER in order to use a custom icon for the balloon tooltip.

On Windows XP Service Pack 2 and later you can use the hIcon member to specify a custom icon.

On Windows Vista and later the NOTIFYICONDATA structure contains the addiional member hBalloonIcon. You can use this member to specify a custom icon if you have set the cbSize member to the correct size of the extended NOTIFYICONDATA structure.