Hey Julian,
Thanks for reaching out. I just received your email as well, but figured I would respond here in case other merchants are looking for this integration as well.
While we're not integrating with PayU in Argentina at the moment, I've added your request to our internal feature request. Should this become available, you will be notified via email.
Thanks for the suggestion - we're always wanting to know what our customers are looking for.
Take care,
Thea
Shopify Guru | thea@shopify.com