the only difference is that sources of 2.6.22.19 should be untarred to src/linux/linux-2.6

to build this 2.6 alpha for wl500g series replace
Code:
CONFIG_CPU_MIPS32_R2=y
by
Code:
CONFIG_CPU_MIPS32_R1=y
in kernel config and adjust the unit name in Makefile.top