phantom power on autoradio

[demal]

Hello, In order to connect the autoradio I have to find a power cable that does not pass for the ignition key so that the device does not loose the settings (radio channels, colors ecc ecc) every time I turn off the car. It seems that in my car such cable it's not already on the iso connector so I have to find a power cable elswere. I came up with 2 option :
1) make a connection on the cable that comes in the ingnition key
2) make a connection on the "four arrows" botton
but the colours of the cables are different from the one on the connector that go into the radio, so how can I find the right cable?
there are others places to make the connection ?
Thanks in advance to every one!

[demal]

Can I use the lighter ?

[demal]

I think I was wrong, the phantom power is the one that goes to the active antenna, I think that I will take the +12 (yellow) from the lighter and connect the phantom power (blue) to the am/fm amplifier, or should I connect it to the ignition key +12 (red)? should the amplifier be always on or is it more convenient to let it shut down with the car ?
on the car where there shoul be the permanent +12 (yellow) there is another unidentified cable. I think that I'll not connect it.

[alexperkins]

What year is your polo?