Importing download urls to MarketPress

I want to import a large number of products into my marketpress store. About 3500.

About half have a download product.

Do I have to use the media manager to first import the products and then get the link from there? I would rather create a directory and just ftp all the products to that directory. I have no need to access the products stored that way except as the download.

Also, will relative links work on the download url, or do they have to be absolute?