I'm using prxdist 2011.05 with Mini2440 BSP 2011.05

I would like to update my CP2102 USB Serial Driver.
I've downloaded the latest driver from :
http://www.silabs.com/products/mcu/pages/usbtouartbridgevcpdrivers.aspx

Looking at the /build-target/linux-2.6.38/drivers/usb/serial It does not
seem like the CP2102 has any dependancies other than the cp2102.c source
file.

What I've done is I made a backup of the old driver source file and copied
the new one.

I've dropped ther kernel comilation ptxdist drop kernel.compile and then
re-compiled it but it does not seem like the new cp2102 drivers source was
compiled.

1.) Is this the correct way to update the driver source?
2.) How can I ensure that the new source is compiled when compiling the
kernel?

Thank you

MC