unattended BIOS configuration for HP server (DL160SE G6)

You should be able to accomplish this using the HP conrep utility provided in the SmartStart Scripting Toolkit. If you're looking at the Advanced BIOS settings, are you trying to change things like the set of low-latency options for the system? Here's a link to an HP white paper detailing the setup for specific low-latency applications. Some advanced BIOS options are covered:

http://h10032.www1.hp.com/ctg/Manual/c01804533.pdf

The idea with conrep is that you can configure a single system the way you want manually, then capture its settings into a file that can be used for other system deployments. An example of syntax:

To configure BIOS low-latency options using the conrep utility in SSSTK: 
1.  Change the current directory to the SSSTK/utilities directory:
cd SSSTK/utilities
2.  To disable Processor Power and Utilization Monitoring, verify that the conrep.dat file contains the
following markup:
<Conrep> <PowerMonitoring>0x10</PowerMonitoring> </Conrep>
3.  To disable Memory Pre-Failure Notification, verify that the conrep.dat file contains the following markup:
<Conrep> <DisableMemoryPrefailureNotification>1</DisableMemoryPrefailureNotificat ion> </Conrep>
4.  Enter the following commands: ./conrep -l -fconrep.dat reboot

Easily the best way of doing this is via the iLO port - it supports SSH, RIBCL, IPMI, SMASH CLP etc. We have pre-written scripts that setup all of our iLO and BIOS as required written in RIBCL. There's lots of help on HP's site about this but basically you'll be using the iLO system rather than a boot CD.