Mate in 13 moves ;-)

Ok, guys, the first diagram shows you the puzzle: : White to move: Mate in 13 moves ;-). Note: White moves his pawns from bottom to top, all of black's pawns are one square before promotion! The second diagram shows the actual mate after 13 moves. In the third diagram u can try to solve this puzzle. Have fun!

Puzzle by Victor Sysonenko and Martin Hoffmann