no ttyusb in dev folder

when i compiled my first Linux kernel (for android), i could not find
dev/ttyusb* in device drivers. who know what is the related branch in
menuconfig?

make menuconfig -->
  Device Drivers -->
     [*] USB support -->
       [*] USB Serial Converter support -->

thanks for your reply!

it is included by default but i have no ttyusb :(

i just compile the Linux kernel with gcc 4.4.1 and use pre compiled file
system (file systems from the company DVD)

Are you using static device nodes? If yes, you must create the ttyusb*
nodes manually.
With a recent kernel you can use 'devtmpfs' and let the kernel create the
device nodes automagically.

SOLVED:

this problem occurs using gcc 4.4.1
now i use gcc 4.5.1 and every thing is OK.

tnx guys