Values of custom product fields will not be found

[be]

Hi,
what could be wrong with my VMart installation?
If I want to search a custom product field value the virtuemart searchmodule it doesn´t found any product.
On this topic: http://forum.virtuemart.net/index.php?topic=111380.msg374203#msg374203
Milbo answered me, that this feature should be included since version 2.0.0.

You can test it here: http://www.aka-verlag.com/index.php?option=com_virtuemart&view=category&virtuemart_category_id=121&Itemid=238&lang=de
with the keyworld "Nneon" it found a book but with "Mari Carmen Suárez-Figueroa" it found nothing.

What can I do to let this feature working. It is essential for the shop, because without this most people found no books.
The most will search through author or isbn-number.

Best regards