What you've described is a fourth.
A 5th and 4th are the same, but where the bass note is what you would normally use as a 5th.
E (7th fret, 5th string) + B (9th fret, 4th string) = E with the fifth
B (7th fret, 6th string) + E (7th fret, 5th string) = E is the fourth
EDIT: (This looked fine as I was writing it, but when it was posted it doesn't seem to work... so, I'm not sure how to write tab on this)
E:7 A:7 D:9 G:9 (where the numbers are the fret, and letters are string obviously)
Just play any normal 5th chord that you would, and play the fret on the string above, and you'll see what I'm getting at.
I've also included a link to a website that shows you the same thing.
http://www.torvund.net/guitar/chords/index.php?page=E4