Re: Proper way to restore from a basebackup without the WAL-files?

If you absolutely must use the pg_basebackup as your source and I'm assuming you have a tarball without any of WAL files, you could expand the tarball into you data directory, and use pg_resetxlog to "fool" the master into starting up. I only say "fool" as it just builds you a blank WAL file which this system can use as its integrity check and properly start.