Product listing in categories ONLY by 10

[Ryoma]

Joomla 2.5.14 e VM 2.0.22c (also with recent previous VM versions).

As you can see:
http://www.poloaviation.it/index.php?option=com_virtuemart&view=category&virtuemart_category_id=42&Itemid=538&lang=en#.UimeLH-uokg
I cannot set the number of products per page. It's 10 even if in my configuration there's no "10" anywhere AFAIK. I tried changing settings a bit just to get a "refresh" but with no effect at all.
I remember that some time ago it was working, then at one point this "10" drawed my attention...

[jenkinhill]

Set your default required pagination number & sequece in Configuration/templates/Set the pagination sequence for the List Box

There can then be overridden by settings on Product Category Form for each category.