Has not been exposed the method to set the profile from the REST API. By default when a user login it is automatically assigned the default profile ( I have not tested if from API happens the same, it is a good practice when users are only logged from API, at the begining call the login method, because this method will create missing folder /okm:trash/userId etc... reviewing the php API I see that has not been wrapped ).
About code into the zip you have all the php classes. You an apply changes into and share with us from here the modified classes. If we consider interesting your changes we will include into the next php release.