code:
Messenger.ContactListWndHandle
try using that? its in the scripting documentation
quote:
The Messenger::ContactListWndHandle property returns the window's handle of the contact list window, if currently opened.
Syntax
This is a read-only property.
[handle] ContactListWndHandle;
Data Type
If the contact list is closed, the return value is 0. The handle is a HWND object and must be used as is. It can be passed as parameter of various Windows API functions like SendMessage.