Pushing to a remote branch named different than the local branch is not memorised

[Ferdinando Papale]

I am trying to push to a remote branch that has a different name than the local branch. The problem is that every time I click on the "Push" button in the interface I need to specify the remote branch again. 
If I used the same name for the remote branch and the local branch this does not happen. 

This is happening with Sourcetree 4.2.8 on Mac