I seem to be able to do full backups, but it doesn't show up in the backups list when I do a "show" command and the "validate" command doesn't seem to do anything; doing an incremental backup, it claims the full backup was never validated, so I can't do increments :-P
I posted on the pg_rman google group, but it seems to be dead.
Operating system is RHEL 6.2 64-bit if that matters.
I thought about using OmniPITR but it doesn't have as many features as pg_rman (e.g., incrementals, showing a list of backups so you can choose which point you want to restore to, etc.)...