I suspect a contributing factor to lack of SLES SP1 updates is due to it being end of life.

With the release of SUSE Linux Enterprise Server 11 Service Pack 2 the former SUSE Linux Enterprise Server 11 Service Pack 1 enters the 6 month migration window, during which time SUSE will continue to provide security updates and full support. At the end of the six-month parallel support period, on 2012-08-31, support for SUSE Linux Enterprise Server 11 Service Pack 1 will be discontinued. Long Term Service Pack Support (LTSS) for SUSE Linux Enterprise Server 11 Service Pack 1 is available as a separate option.
From http://www.novell.com/linux/releasen...SE-SLES/11-SP2