Issue with Dynamic Attribute Linking (no product id available)

I use this plugin with Google Universal Analytics, I’ve got all settings enabled including enchanced ecommerce, except “Use Enhanced Link Attribution”.

In GA Admin panel I try to enable dynamic attributes for remarketing (Audiences Definitions -> Dynamic Attributes). But there is no possibility to choose normal product id. I’m able to select only “Product SKU”, “User Defined Value” or 50 (sic!) “Custom Value (Key x)”. My product feed is based on product id, and I’m stucked. Is there any configuration to pass product id? Or is it possible to add this property?

Please help.