Facebook "Send Dialog" - how to track referrals

I am trying to use Send Dialog of facebook on my site (http://ift.tt/1sEcgXR)

I need to know if there is a way to track Referrals with this dialog? just as there is a ref param with Send Button (http://ift.tt/1jaORGY).

I tried adding ref in the FB.ui as a param, but doesnt work..