Just popping in? Entries for a text entry box can be confirmed by a shortcut key (in your case a TAB) or by clicking on a Submit button. I was wondering if you couldn't use the technique described in this blog post to make the Submit button invisible to the user and have that submit button on top of the second TEB:
http://blog.lilybiri.com/one-submit-button-for-multiple-text-entry-box
In that case the associated user variable is populated exactly in the same way. You can choose validate for the TEB and use the normal Success and Failure actions. Not even conditional actions should be necessary in that case.
Maybe I don't understand the question totally, and I miss to see how you were configuring it for the moment?
Lilybiri