Only setting a password would not make much sense, as SMB is not supported as well on WEC2013.
Either we would have to port SMB server to WEC2013 or you find an othe way to exchange files. One feature, that is still there on WEC2013 is the FTP Server feature. In our standard image, this is enabled. So you would only have to manage the FTP passwords and directories somehow. Most things can be configured through the registry directly. For setting the password, you need some coding. We have a sample command line tool project, that allows you to add users or update user credentials. You can download it from here.