I've gaven my kindle an network-IP connection in my WLAN before the JB.
No Idea, how to give it an IP during Jailbreak.
Just gone now in the Diat Menue U) USB device mode, made step 1.
After this I had to reset my device with the power-Button, because it unfortunaly wont reboot with menue D), R), Q).
This is where I stuck. - I think, my only problem is that my kindle wont reboot normaly on the last menue-selection