database role for backups?

I tried to create make backup my postrgresql cluster with amanda.
And I had to create database superuser.

I tried to create no-superuser role with only "replication" privillege,
but after run backup I got:

--8<---------------cut here---------------start------------->8---
2013-05-06 13:33:02 CEST ERROR: must be superuser to switch transaction log files
2013-05-06 13:33:02 CEST STATEMENT: SELECT file_name from pg_xlogfile_name_offset(pg_switch_xlog())
--8<---------------cut here---------------end--------------->8---

So my question is:
Can I establish postgresql role which is _not_ superuser and can execute
above statement?
KJ

PS. does news.postgresql.org work? I got 'unknown host'

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