XMPP adding User to Roster

Hi,
I am looking into using the XMPP module and read through the documentation. While most is pretty clear(like getting the Roster of a user) i can’t see an implementation to add one. Can i simply create a FXMPPMessage with the desired query and send it through the Messages interface?

If this is the case, is it correct to set ToJID (and when seinding RecipientID) to an empty string? Or how do i do it correctly?(if possible)