Rules not triggered with og_invite_link

The og_invite_link module allows the group admin to invite users to their group by entering the username on an 'invite' page. Essentially, they are pre-approving the user and when the user clicks on the link in the email that is sent, they are automatically logged in and are at the group page.

I need to give the invited user a role but neither the 'user approved to group admin' or 'user subscribes to group' is triggered during this process so I can't figure out a way to give the user the role they need to have.

Is there another way to give a user a role associated with a particular type of group? I can't do a 'blanker' role because I have other types of groups.