Problem with Encode module

Hi All,

I encountered some problem with the Encode module when I convert some
Japanese contents from shift-jis to utf-8. Basically I am using the
from_to subroutine to do the job. All work well except for those number
inside a circle characters (8740 ~ 8754). The unicode range for those
characters is 2460 ~ 2473. However, the from_to doesn't convert them
correctly. For 8740 (1 inside a little circle), what I got was "FFFD
0040".  

Does anyone have any idea what the problem is? Is this a known issue or
there is something wrong with the original shift-jis text? Any advise is
very appreciated.

Thanks,
Jianyang