Flash Self Programming Question

Hi All,
I wanna self program the flash memory of AT91SAM7S256 by my own code
instead of via USB or programmer.

According to the AT91SAM7S256 Datasheet, the data are stored in a latch
buffer before execute programming command. But it does not tell how to
store data into lactch buffer and how to read data from latch buffer
when verifying.

What Latch Buffer? Does anybody know how to do that?

Thanks.

Min Ge