How do I place the IM icon in my signature

[Simplicity]

I use the 'online status indicator' for MSN Messenger in my signature and was wondering if there is a way to copy the MSN button to the signature that would allow the user to click it and send a message to my IM. I know that this is already available, but would prefer to have the button in my signature rather than above the post.

I cant simply copy the shortcut url that the button uses as it would just redirect to the thread and not bring up the msn popup window.

Any help with this would be greatly appreciated