ilovefuzz.com

Have you tried the drop tuning mode? Should be button on the back right of the pedal (or maybe on the right side for the mini). Just push that down until it says 'B' or whatever your lowest open stringed note is (note: it doesn't go down to A). Page #11 of the pdf. Hope that helps!

http://www.tcelectronic.com/media/Polytune_mini_US.pdf