S5830 custom kernel topic

Well I planned to build a kernel for S5830 from samsung msm 7x27-cm-11.0 source . I obtained the zImage successfully. Later on I used Koush's AnyKernelUpdate.zip.
1- I placed the zImage in the folder named Kernel in the AnyKernelUpdate.zip
2- Modified

Code:

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mount("MTD", "system", "/system");

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with

Code:

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mount("ext4", "EMMC", "/dev/block/stl12", "/system");

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When I flash this zip from CWM it gives Installation aborted.
Any help?
Thanks in advance.