Vista - Vista Contacts - extended characters import

I am trying to import my Outlook Contacts into the Vista Contacts folder.
Many of the Outlook Contacts have extended characters, e.g. á, é, í, ó, ú,
ñ, etc. The CSV file that I created from Outlook correctly displays the
accented letters and the Spanish "ñ" but when I import the contacts into
Vista Contacts, the accented letters in names like Fernández, Pérez and
Concepción are displayed as a symbol resembling a square.

Importing a vCard works but I have hundreds of contacts and I haven't been
able to save all of them as a single file. Saving and importing them one at
a time would take hours.

How does one import contacts with Spanish and French names?