Do you mean to be able to send upates to shopify when products in the FileMaker db change?
It sounds like you need to use their API : http://api.shopify.com
You'll need a plugin that speaks HTTP. There's our free BaseElements plugin ( http://www.goya.com.au/baseelements/plugin ) or there is the Web Services one from beezwax ( http://www.beezwax.net/products/wsp ) or Troi's URL plugin ( http://www.troi.com/software/urlplugin.html )
Either way you'll need to code up the interations with the API manually depending on what you're changing and where.
Basically i want that when a product is sold in the physical shop (where I use Filemaker Pro) the stock changes automatically on the webshop and vice versa.
I'll have a look at the links you have mentionned!
Have a nice day!