It looks correct. The procedures you mentioned also should work. Have you also checked pin mapping from your FPGA *.ucf file with connector pin?
00h with 02. Reset.
42h with 04. Enable digital function.
25h with 01. chanA test pattern 0.
2Bh with 02. chanB test pattern 1.
But nothing happens. The spi is clocked at 5MHz.
Thanks,
KW