Does the new tab automatically become the active tab? If so, then you would use the code from the earlier link like this:
$oIE3 = _IEGetActiveTab()
If this doesn't work for you, then you will need to provide a more detailed explanation of the situation you are attempting to address. All you've told us thus far is that a new tab is launched when you click the submit button, which isn't alot of info to go on.