Love This Tune..but Have No Clue What They're Saying.

Might be a long shot but it sorta sounds like it's to the melody of Simon and Garfunkel's "Mrs Robinson". Which ManC Supporters also use for their 'Here's to you Vincent Kompany" chant.
They are indeed singing to the tune of Mrs Robinson. The lyrics they're singing are:

Oh VfB hier im Stadion,
schlägt dein Herz, lebt deine Tradition. Oh VfB.

Solang wir in der Kurve steh'n,
wird auch deine Fahne weiter weh'n. Oh VfB.

Which translates as something like this:

Oh VfB, here in the stadium
Your heart beats, your tradition lives. Oh VfB

As long as we stand in the Curve (the designated "ultras" area of the stadium)
We will still fly your flag. Oh VfB.