Import to update product properties

Hi all,

we want to add a property to hundreds of products. And do so now and then.
How do you create an import file for properties of existing products? And if it’s possible, what does the csv file look like?

(In the past we made an import profile for tags. Just 3 columns, productNumber, tag,id ), but now we have to add key value pairs to the file?)

So, I got it working.
Create a profile. Map those 3 to the same names.
Advanced settings: Product->productNumber and properties->id
Create the csv. productNumber,properties,id
for properties use the id (you can look them up by using the export function and download all properties)
leave id empty.