If you want to adjust outlook express to settle it to minimize on taskbar, you can do it with the help of registry settings.
Start registry editor and go to the following key
Hkey_Current_User \ Software \ Microsoft \ Office \ 10.0 \ O Utlook \ Preferences
Modify / Create Data Type Dword Named (Mintotray)
There are two options to settle Value data (0=disabled and 1=enabled) when you finished the process exit from registry and reboot your system
Start registry editor and go to the following key
Hkey_Current_User \ Software \ Microsoft \ Office \ 10.0 \ O Utlook \ Preferences
Modify / Create Data Type Dword Named (Mintotray)
There are two options to settle Value data (0=disabled and 1=enabled) when you finished the process exit from registry and reboot your system