Puzzle of the week #77

Chess Diagram: 

[Event "Puzzle #77"][Date "2009.07.10"][Result "1-0"][SetUp "1"][FEN "4k1K1/6P1/8/8/8/8/7r/5R2 b - - 0 1"]

Wikipedia presents this player as follows:
"Alessandro Salvio (c. 1570 - c. 1640) was an Italian chess player who is considered to be the unofficial World Champion around the year 1600. He started an Italian chess academy in Naples, Italy, and wrote a book called Trattato dell'Inventione et Arte Liberale del Gioco Degli Scacchi, which was published in Naples in 1604."
His chess contribution is absolutely remarkable and has passed the test of time with flying colours. Year after year players from all over the World are learning from his written teachings. The above position was put together by Salvio in 1634 and should be an easy one for all of you this time. Your tasks are:
a) Black to move; White still wins
b) Explain your solution

This time you should be able to write a nice explanation, especially if you paid attention in class and wrote down our conclusions properly. Total available points for this puzzle is 20. The answers will be published next week together with puzzle #78.

Puzzle #76 solution:
A methodic approach should have been used this time: look at all possible options (3 in total) and analyse them. This analysis should have been based on a clear plan, as we discussed in class:
1. Get the Black King out of there.
2. Advance the pawn to the 7th rank.
3. Use Lucena position when necessary.
Unfortunately the answers were not very good, but I hope the discussion in class clarified what should have been done. Rook endgames are not easy to learn and play, but once you do learn them there's a lot of rewards.
See solution:

[Event "Puzzle #76"][Date "2009.07.03"][Result "1-0"][SetUp "1"][FEN "3k4/7R/3K4/3P4/8/8/8/2r5 b - - 0 1"]1...Re1 (1...Ke8 2.Rh8+ Kf7 3.Kd7 Ra1 4.d6 Ra7+ 5.Kc6 Ra6+ (5...Ke6 6.Re8+ Kf7 7.d7 {White wins}) 6.Kc7 Ra7+ 7.Kb6 Rd7 8.Kc6 Ra7 9.d7 {White wins}) (1...Kc8 2.Rh8+ Kb7 3.Kd7 Rg1 4.d6 Rg7+ 5.Ke6 Rg6+ 6.Ke7 Rg7+ 7.Kf6 Rd7 8.Ke6 Rg7 9.d7 {White wins}) 2.Rh8+ Re8 3.Rxe8+ Kxe8 4.Kc7 {White has reached a won King and pawn endgame}

Correct solutions:
Joshua, Andy Q - 12 points
Alex, Wilson - 8 points
Karl, James - 5 points
Marcus - 2 points

Joshua - 32 points
Andy Q - 30 points
James - 23 points
Katerina, Andy Y, Alex - 20 points
Karl - 17 points
Wilson, Marcus - 14 points