How to restore a SQL-ASCII encoded database to a new UTF-8 db?

Hi,

I have a database that was created with SQL-ASCII encoding
(unfortunately).  I ran pg_restore to load the struct and data into a
new database with UTF-8 encoding but no surprise- I'm seeing this
error for a number of tables:

pg_restore: [archiver (db)] COPY failed: ERROR:  invalid byte sequence for encod
ing "UTF8"

Any idea on how I can copy the data between these databases without
any data loss?  For some reason I thought that a conversion to Unicode
would be easy.

Thanks