rear antenna

hello,

i would like to start a little project but i need some help: after retrofiting to Columbus i wish to use rear window as second antenna.

From elsa i see that there is a connector to rear window that i don't know where it is (red square). Is a supplimenatry wire on rear window?

somebody know if that rear window are different? in ETKA i didn't see that are 2 codes for rear window. is only one.

I found on dismantle service a lot of radio amplifier for  golf V with diversity antenna and maybe i can use them.

Any ideas?

thank you