windows messenger does not appear on taskbar

If I set windows messenger to start every time I log on to
windows xp pro, it does not show on taskbar, yet task
manager shows that windows messenger hasd started.
When I manually start windows mesenger using the shortcut,
it appears on the taskbar. Also, if I start it using the "run"
with the /background switch, it appears on the taskbar.
In conclusion, if it is set to automatically start, it does
not draw, but if I manually start it, it draws on the taskbar.