[Q] [RAY] How can i enable "fastboot"-mode on the device?

[Kierro_Hun]

hello

in first, sorry for my bad english, i use google translator

i would like to ask for some help

i have a xperia ray (st18i), manufact. date is 12w17
this device is already network-unlocked via an NCK-code
but it has not "fastboot" mode

i want to change the kernel so, anyway...

so, have you any idea, how can i enable the fastboot-mode?
or can you help me, to make from any boot.img to kernel.sin or kernel.ftf
otherwise is it possible to upload a kernel in "flashmode" anyway?
example, embedding a kernel.sin in a stock ".ftf" rom?

thanks in advance

Kierro