Default If I flash a custom kernel (googymax for e.g.) I get (no service)

I want to install a custom duel-boot kernel on my s3
now I'm using this ROM : http://forum.xda-developers.com/show....php?t=2569180
I had the broplem of (not registered on a network) before
And I solved it by flashing patched modem & patched kernel
if i try to flash custom kernel i get (no service) status
then I have to flash the patched stock kernel again to make my network work
Is there any way that enables me to flash the custom kernel without losing my network ??

I also tried to flash init_d script then flashed the kernel but it didn't work