How To Remove an Account in Samsung IM

Hello I have some Questions about Samsung IM in SGS..

1) I use Samsung IM to connect with my Yahoo Messenger (YM), and I realize that we can add more than 1 YM account in Samsung IM, so that I tried to add another account and it's works. But.. now I want to remove the additional account but still don't know how to do it.
Can anyone help me how to remove an YM account in Samsung IM?
(when I klik menu button only 2 options there : sign out and detail)

2) my Samsung IM was work perfectly until this morning I realize that it going online by it's self. My friend told me that he saw my account was online this morning (in YM), he sent me a chat and the text go to my SGS. I never online with my SGS more than a week.
Anybody has Idea why this is happened? I thought it was a virus or something like that, but I never download or install anything recently.

please help me..
thanks before..

Note : my SGS is in Froyo..

yes this works:) long press & remove account. If you don't want to sign in automatically make sure you remove that check mark when you create the account.