Whoa...
We're mixing things up and (potentially) going to confuse the OP.
Quite simply, pins 2 and 3 are reversed on the pre-amp (w/ respect to what is normal in the US). In all reality, this should make absolutely no difference in what is "seen" by the amp, as the signal on pin 2 and 3 are, regardless of the "European method" or "USA type of PIN arrangement", a simple signal inversion IN THIS SITUATION. The suggestion to reverse the speaker cables is simply a hyper OCD suggestion (and is technically, not necessary).
OP, you'd probably be better off if you ignored this thread, plugged-in some balanced XLR cables, and enjoyed the music.