heres how to add ur custm buton

id back up ya registry before doing it tho

HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Extensions\CmdMapping]



Make a note of the value of NextId, then edit "NextId" and add 1 to the existing number.

Create a new REG_DWORD value named {3000AA00-00A0-0000-AA00-AA0AA0AA0A00} and set its value to the initial value of "NextId" before you added 1.


Next, migrate over to the following key:

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Extensions\]



Create a new key named "{3000AA00-00A0-0000-AA00-AA0AA0AA0A00}" (Must match REG_DWORD from above)



Under this newly created key enter the following REG_SZ values, a brief explanation of each is provided:



CLSID values can not be modified, this lets IE know that it is a toolbar extention.
"Clsid"="{1FBA04EE-3024-11d2-8F1F-0000F87ABD16}"



Text that will display on the button.

"ButtonText"="Outlook"


Not Important, you are not adding this to a menu option, but it is still required.

"MenuText"="Open &Outlook"



Not Important, you are not adding this to a menu option, but it is still required.
"MenuStatusBar"="Open Outlook"



The path to the executable that you want the button to launch, this may also be a URL, make sure to begin it with "http://"
"Exec"="C:\Program Files\Microsoft Office\Office10\OUTLOOK.EXE"



Icon file that is used, either point it directly to an .ICO file or if using an executable you need to figure out which index and append it to the end of the path following a comma as below, normally it will be 1"
"Icon"="C:\Program Files\Microsoft Office\Office10\OUTLOOK.EXE,1"



This is the icon that will show up when you mouse over the button, same rules apply as the initial icon.
"HotIcon"="C:\Program Files\Microsoft Office\Office10\OUTLOOK.EXE,1"