Added doc about charsets

diff --git a/InternetSecure.pm b/InternetSecure.pm
index 1442894..5ffc99c 100755 (executable)
--- a/InternetSecure.pm
+++ b/InternetSecure.pm
@@ -525,9 +525,17 @@ When using a products list, the B<amount> field passed to B<content()> should
 be left undefined.
 
 
-=head2 Character encodings
+=head2 Character encoding
 
-...
+Since communication to/from Internet Secure is encoded with UTF-8, all Unicode
+characters are theoretically available when submitting information via
+B<submit()>.  (Further restrictions may be imposed by Internet Secure itself.)
+
+When using non-ASCII characters, all data provided to B<submit()> should either
+be in the current native encoding (typically latin-1, unless it was modified
+via the C<encoding> pragma), or be decoded via the C<Encode> module.
+Conversely, all data returned after calling B<submit()> will be automatically
+decoded.
 
 
 =head2 products_raw