The way I figure it out is, the order of the pins on the PS2 receiver is:
Dat - Cable 1 - Black - P12
cmd - C1 - Red - P13
GND - C2 - Black
+5v - C2 - Red
Sel - C1 - Yellow - P14
CLK - C2 - Yellow - P15
I put some blank lines above as the wires in the PS2 receiver are grouped in 3 wires per group. On some of my receivers I put a piece of tape on top of them and label them as such. The P numbers are the Bot Board 2 pin numbers.
Ok Now which pins do you use on an Axon? It probably depends on what software you are using to control it. On My Axon2 using my own functions, I use:
#define PS2_DAT K4
#define PS2_CMD K5
#define PS2_SEL K6
#define PS2_CLK K7
I believe these pins are available on the Axon as well. If you are using webbotlib and look at his example, I think he uses pin F0 for the select and for a software version of an SPI bus he uses pins B5, B6, B7 as B5=MOSI(CMD), B6=MISO(DAT), B7=CLK and F0=SEL
So which pins you choose is up to you, you just need to tell which ever software what pins you ended up using.