Cannot use custom permissions for both Facebook and Linkedin

Steps to reproduce:

• add custom scope permissions for both Facebook (see http://code.google.com/p/socialauth/issues/detail?id=177) and Linkedin (see http://stackoverflow.com/questions/30212290/issue-with-linkedin-integration-using-socialauth-in-android and https://developer.linkedin.com/support/developer-program-transition)

  #LinkedIn
  api.linkedin.com.consumer_key = XXYYY
  api.linkedin.com.consumer_secret = XXYYY
  api.linkedin.com.custom_permissions = r_basicprofile,r_emailaddress
  
  #facebook
  graph.facebook.com.consumer_key = XXYYY
  graph.facebook.com.consumer_secret = XXYYY
  graph.facebook.com.custom_permission = email,user_birthday,user_location,user_photos,user_groups,friends_photos,friends_groups
  

  Result:

• the redirect URL for Linkedin is using the scope from Facebook