I finally solved it.
1.Bc3+ Kc4 2.Bd2+
This has to be done first to clear e1 for the wN.
The N must clear the a5-e1 diagonal, but still end up holding d3.
3...Kd3 4.Ne5+ Kd4 5.Nf3+
If he stays on e5, the planned Bc3+ becomes mate.
5...Kd3 6.Ne1+ Kd4 7.Bc3+ Kc4 8.Ba5+ Kd4 9.Nf3+
Not yet Rd2+, because of the reply ...Nd3+!
9...Kd3 10.Rd2+ Kc4 11.Rb4+
The justification of Ba5 emerges...White gets two R/B batteries that allow Bd7 to give check without mating.
11...Kc3 12.Rb6+ Kc4 13.Bb5+ Kb3 14.Be8+!
14.Bc6+? takes away wN's return square.
Now, White only needs to reset his pieces.
15...Kc3 16.Rbb2+ Kc4 17.Rdc2+ Kd3 18.Ne1+ Kd4 19.Bc3+ Kc4 20.Bd2+ Kd4 21.Nf3+ Kd3 22.Ne5+ Kd4 23.Nc6+ Kd3 24.Nb4+ Kd4 25.Bc3+ Kc4 26.Be1+ Kd4 27.Bf2+ Rxf2#