Polarity Conundrum

I recently bought an Audio Research LS-15 preamp and an Accuphase P-450 power amp from other Audiogoners. They will be connected via the balanced XLR ins/outs, but the polarity scheme is the opposite in each piece. The LS-15 is Ground/Positive/Negative, the P-450 is Ground/Negative Positive. Someone(s) on another thread suggested that the simple way to address this polarity inversion is by swapping the speaker leads to the amp to the opposite connectors.
Instead of positive to positive, you go positive to negative/negative to positive on the amp's output terminals. Can it be that simple? The Audio Research manual says to contact them when this situation is encountered, but if this simple fix will work, I'm all for it. What say you guys?