SQL error when adding product variants manually

I have encountered a couple of issues adding Variants.

1. If I switch off "Generate variants automatically" in advanced settings, go to a product without characteristics or variants and add characteristics to it, and then click on "Manage Variants" an SQL error occurs. It seems this view assumes there are always going to be variants

1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ') ORDER BY `ordering` ASC' at line 1 SQL=SELECT `ordering`,`variant_characteristic_id`,`variant_product_id` FROM ap_hikashop_variant WHERE variant_product_id IN() ORDER BY `ordering` ASC

2. When adding characteristics to a product the multi-select checkbox at the top of the select column doesn't actually do anything, it's necessary to select characteristics individually which is a pain if you have a lot of characteristics on a lot of products (see attached capture3.jpg)

I hope you can address these two problems,

Thanks,

Ian

-- url of the page with the problem -- : not yet online
-- HikaShop version -- : 2.2.1
-- Joomla version -- : 3.1.5
-- PHP version -- : 5.3.1
-- Browser(s) name and version -- : Firefox 17.0.1

That's excellent support, thank you Nicolas. I have another question which I'll post as a new topic.

Ian